Hi Stephtut,
Lots of questions which need lots of answers so one at a time 
The mattresses at Mt Vernon Sleep are all the “natural” (blended) versions of the PLB. It’s too bad they don’t also carry the Nutrition which is in between the Nature and the Beautiful.
If you enter your zip code here on the PLB site and put in a radius of 100 miles it will show you all the retailers that carry them in your area. Healthy back carries their own version of them that uses Celsion latex (a more temperature regulating version of talalay but it’s still blended) and I know they also have at least one of the all natural versions on their floor. While the staff is different in each of their outlets, they have been knowledgeable and very helpful in my conversations with all the outlets I’ve talked with.
The specs of the PLB blended lineup are in post #4 here. The all natural would be similar but slightly different because the 100% natural talalay comes in slightly different ILD’s and would also have slightly different properties and feel. Both their blended and natural talalay are Oeko-Tex standard 100 class 1 certified which means that they have been tested as being safe for babies in terms of chemical content and offgassing although I do understand that some people with multiple chemical sensitivities may still prefer the all natural just for peace of mind even though it may not be as durable.
Rather than try to suggest a “best” layering from afar … because of your unique circumstances I would always suggest that local testing with the help of someone who is knowledgeable and experienced in “fitting” a mattress to people with unusual needs and preferences is much more helpful. The knowledge and help of the outlet you go to can be one of the most important parts of finding your best mattress. Clearly the person you were dealing with does not fit into this category and it appears that you know considerably more than they did (which unfortunately isn’t so unusual in the industry when someone has done some research).
I would also agree with you that the Pamper with a 1" comfort layer over a very firm support core would likely be too firm and the Beautiful with 5" of softer latex (3" 19 ILD and 2" of 24 ILD) over a slightly less firm 36 ILD support core would likely be too soft. In the PLB … the odds are that the Nature or the Nutrition would be closer to your needs.
While what they were saying about a foundation is true (that latex is more breathable and a solid foundation may not be an issue) … my own personal preference would be for a strong and rigid slatted or steel grid foundation anyway because it would both further reduce the risk of “nasty critters” and also improve the overall breathability of the mattress and in your circumstances even small incremental improvements can be important.
As you mentioned … Habitat uses good quality materials but there are many better options both online and through local purchases.
[quote]1. Do you agree with my assessment of the responses I received from the local retailer regarding PLB?
a. A solid foundation rather than a slatted foundation may be acceptable for a latex mattress because of the pincore construction of the latex mattress, particularly with a fabric layer between the solid wood of the foundation and the bottom of the latex mattress to remove moisture. However, due to my allergies, a safer approach is a slatted foundation.[/quote]
I agree completely with your assessment that a slatted base would be better for you.
This would definitely be the natural rather than the all natural.
Yes it does and their comments are absolutely inaccurate. Some outlets even list the layering.
This is correct. The mattress manufacturer generally provides the warranty and the outlet is the one who offers any exchange or refund policies.
See the previous link to the PLB retail finder site.
The Q & A from the PLB site is probably the most accurate in terms of the difference in feel between the two. the all natural would be a little more elastic and denser (a bit more supportive) while the natural would be lighter, and slightly more pressure relieving. For most people the differences would not be major.
The natural is typically 70% synthetic rubber (SBR) and 30% natural rubber (NR) while the all natural line is all NR. This can vary though in terms of the blend used and many people believe that the all natural uses a very small percentage of SBR for consistency and ease of manufacturing. Bear in mind too that the rubber content of the foam is only about 90% or so of the material and soaps, curing agents, antioxidants etc are also part of the formula although any residuals are washed out through their extensive washing process.
The natural is in the previous link. The All Natural would be similar but would use the closest ILD’s of the all natural talalay which are listed on the Latex International site here. Bear in mind that latex ILD’s are not exact and an average of 9 different measurements across the surface which may vary by about 4 ILD (which is not noticeable).
These would be very difficult to compare partly because the layering and materials are different. The differences would be partly because they use different support materials (the HF is dunlop while the PLB is Talalay), partly because they use a different ticking/quilting (PLB is an unquilted stretch knit while the HF is a wool quilted cover), and partly because how it felt to you would very much depend on your individual weight distribution, how you sank into the mattress, and which layer or layers you felt the most. If I had to guess they would be similar in terms of pressure relief (because the upper 3-4" would be fairly similar although the PLB may be a little softer) and the support of the PLB would be a little firmer but this would depend on how deeply you sank into the mattress because dunlop gets firmer faster than talalay and the lower ILD support layer would “catch up” to the talalay with deeper compression. the PLB would be more adaptable to different positions because it is thicker and there would be less chance you may feel like it was bottoming out (becoming very firm in certain positions or with movement). Dunlop would also feel more “dead” while Talalay also feels more lively although this too varies between different people depending on weight and perceptions.
You could come “somewhat close” to matching the stats through various “choose your own layer” online options at a better price but because small differences in layering and materials can sometimes make a larger than expected difference in how a mattress feels … it would not be an exact match. There are many online outlets however that will allow for layer exchanges (either by re-arranging the layers or by actually exchanging them for softer or firmer versions) at a very reasonable cost. The members of this site who specialize in online and telephone assistance and purchases that can be shipped anywhere in the country are listed in post #21 here. They all offer different options at different prices however they all have excellent value.
Outside of outlets like these, many local manufacturers offer adjustments to a mattress at a very nominal charge within a certain time frame. With many retail outlets, the terms, restrictions, and fees of a comfort exchange can turn it into a profit center rather than a consumer benefit, is restricted to what they carry, and they may not carry another mattress with the materials you want that is suitable for you. In many cases “assurances” of a comfort exchange is a sales technique and a means to “lock you in” to the profit of buying something in their store. While this is not always the case, it is certainly very common. A comfort adjustment (where they remove a layer and replace it with another and then sew the mattress back up) or a legitimate comfort exchange that is more in your interests than theirs is far less common.
If you mean position adjustable where the head and feet can be raised or lowered but they provide a firm solid foundation when flat … they can be very useful in certain circumstances (such as certain medical conditions like acid reflux or back sleepers who snore) but besides this they are also a great option for those who like to read or watch TV or a movie in bed. If you do decide to go in this direction make sure the weight of both of you and the mattress are within the weight ratings of the model you are considering.
If you mean a tension adjustable base where different areas can be made softer or firmer … they can also be useful as a means of fine tuning pressure relief or alignment but their affect depends on the thickness of the mattress and I personally would put my focus on testing mattresses that worked for your needs and preferences on a firm slatted base (either position adjustable or solid) where the mattress layering did as much of the work as possible because this is much more widely available. If you test a specific combination of tension adjustable base with a specific mattress and the combination works perfectly … then I would purchase them both together. I would avoid testing a mattress on a firm slatted foundation and then buying a different type of foundation unless it was absolutely necessary and not until you had slept on the combination you purchased for longer than the several week adjustment period that is common for all new mattresses.
While I’m happy to provide ideas and layering suggestions that can be a starting point for field testing or suggestions based on a reference point or specific feedback on a specific mattress … to make a suggestion based on height/weight theory about what your ending point should be based only on the layering and ILD’s of the layers and not taking into account the other components of the mattress besides just the latex or being able to see how you sank into a mattress or feeling how you felt would not be doing you any favors.
The better manufactures who do this for an online purchase are very familiar with the smaller details of their specific constructions and materials and how they have worked for a very wide variety of people and for an online purchase they are always in the best position to recommend a specific layering for their mattresses based on your own field testing and feedback and more detailed conversations.
For local purchases … the ability to see how you lie on a mattress and the specific real time feedback that you can provide is always more accurate than long distance suggestions. There are some height and weight guidelines here and some sleeping position guidelines here that may help to explain why certain layerings feel the way they do or how different changes can affect pressure relief and alignment. If you have specific feedback in pressure relief and alignment terms for a specific mattress, my suggestions may be helpful in terms of a change in ILD or layering that may improve pressure relief or alignment or come closer to your preferences and I’m happy to make them … but a local outlet that can actually see you and is right beside you with real time feedback and who has the knowledge and experience to help you make your best choices would always be better than me
In essence … the more the person knows that you are working with and the more they have your interests at heart rather than their profit … the less you have to know and the better your choices are likely to be. This way you can focus more on the pressure relief, alignment, and overall feel without the sometimes overwhelming research into the specifics of construction which can be confusing and sometimes counterintuitive.
A trip to Savvy Rest in Vienna may be worthwhile because they make mattresses where you can choose your own layering in 3" layers of either 100% natural Dunlop or all natural Talalay. while they use very high quality materials … they are very focused on natural products and they are slso very similar to several of the online options I listed earlier and would provide an excellent model for an online purchase at a much lower cost using similar layering.
Hope this long reply answered most or hopefully all of your questions but if not feel free to let me know what I’ve missed.
Phoenix