Hi jdp83,
It would be better to ask some of your questions of the manufacturers themselves who are much more familiar with every detail of their products and how they interact with different body types and sleeping styles than I am (they each have real world experience with many thousands of customers of many different body types and sleeping styles) which puts them in a much better position to answer more specific questions about the specific mattresses they sell. I’d certainly be happy to give you some general feedback about some of your questions though.
This could be because it is both too soft and too firm. Every mattress needs to be soft and thick enough in the comfort layer to relieve pressure and also firm enough in the support core to hold up your heavier parts and keep the spine in a neutral algnment (stop the heavier parts from sinking down too far). The foam in the upper layers of the Beautyrest has almost certainly softened which means you would “go through” it more and feel the firmness of the lower layers (which could be the reason for the arms falling asleep which is usually … but not always … a sign of not enough pressure relief) and the same foam softening could also lead to an overall feeling of the mattress being too soft and not supportive enough (not holding up the heavier parts well enough).
Do you know the model of the iComfort you liked. They go from firm to soft so knowing the specific model may give a sense of the overall feel you prefer. Bear in mind too that memory foam and latex (as you know) are completely different materials and one doesn’t “translate” into another.
This is true and softer materials in the upper layers of a mattress will soften and wear out faster than firmer materials deeper in the mattress. The other side of this though is that softer materials are also generally more pressure relieving and a combination of both can be used to provide more customized combinations of both relieve pressure and support. Because the upper materials do wear out faster … it can be an advantage to have a separate topper or an exchangeable layer and zip cover so that just the material that wears out first can be replaced. While latex is a very long lasting material, this can be an advantage here as well. Just a single solid core without any softer layer will work for some but not for others … particularly those that prefer a softer or thicker comfort layer.
I’m surprised he didn’t know the details of his springs. It’s probably an offset. They also make many two sided innerspring mattresses which are also a durability plus compared to one sided mattresses. You are probably correct that the comfort layer (in addition to the quilting that you mentioned which is generally thinner than the comfort layers over the innerspring) may have been too thick with a topper and the softer comfort and quilting layers that were already part of the mattress. Keep in mind though that “theory” about the thickness that a mattress “'should” be is not as important as your own personal experience in testing specifically for pressure relief and support. Your testing and what your body tells you is always more important than the “numbers”. The numbers (what I call quality specs) will tell you about durability … not how suitable a mattress will be for your needs and preferences.
If you go to their retail outlet locator on their site … you will find a few places that carry the PLB which would give you a chance to test their other models and also their 2" and 3" topper (which is very soft) on the Pamper. I would call them first though (as with any outlet you plan to visit) to find out what they carry.
@ Flobeds and SleepEz comments
Flobeds is a high quality choice but as you mentioned they are also quite pricey and there is a significant “value” difference between the two. I would also not pay any attention to an “automated” firmness selector without a more detailed conversation to go with it. These are OK as a general guideline … not as a means to make any final choices IMO.
Post #2 here has a general comparison between SleepEz and Flobeds and a search on vZone (you can click this) will bring up some posts with my thoughts about this as well.
In general though … trying to “design” your own mattress based on specs can lead to more confusion and often “paralysis by analysis” without the specific experience and testing of many different layer combinations to “translate” the specs into real life terms that relate to your own unique needs and preferences. In general your own experiences in testing a mattress are more accurate than “theory at a distance” but the additional “risk” of an online purchase can be greatly lowered with a more detailed conversation on the phone. They have the experience with a large customer base to be able to help you much more effectively and you will have a much better sense of whether an online purchase is within your “risk tolerance”. For the large majority of people … an online purchase with layer exchanges can be a great choice and will end up well within the range of meeting your needs and preferences. For a small minority though … they can be more challenging to “get it right”. Bear in mind that if you are close then there are also many options that can make 'fine tuning" adjustments that may be necessary without even having to exchange a layer (protectors, mattress pads, and toppers) as long as the basic choice is close to what you need and prefer.
This thread will outline all the different foundation options that you have from very low cost to higher costs and provide some good sources of both. In most cases … I generally suggest to go with the foundation that the manufacturer recommends but there are lower cost options available for those who want to include a little extra research. Most adjustable foundations would fit inside a sleigh bed but I would measure first just to make sure.
Hopefully this has helped but if you have more questions (or if I’ve missed any other than those that the manufacturer would be in a better position to answer) … feel free to ask.
Phoenix