Hi sdemmet,
You were getting some misinformation. “Laytex” is just a different and less commonly used spelling for “latex”.
“Latex” just means a rubber particle suspended in water so “pure latex” would apply equally to latex made from synthetic rubber, natural rubber, or a blend of both. Latex layers can be made either using the Dunlop process or the Talalay process and either one can use natural rubber, synthetic rubber, or a blend of both.
Latex that is made completely from natural rubber (either Dunlop or Talalay) and doesn’t contain any synthetic latex in the mix is generally referred to as 100% natural latex although there are also some other “ingredients” that are used in the formulation to make it possible to turn the liquid latex into a foamed latex layer (see post #18 here).
All the latex you are likely to encounter (either Dunlop or Talalay that is made with either natural or synthetic rubber or a blend of both) will have a reliable certification such as Oeko-Tex, Eco-Institut, or Greenguard Gold (see post #2 here) or C2C (see post #13 here) and based on actual testing I would consider any type or blend of latex to be a very “safe” material in terms of harmful substances and VOC’s.
The choice between different types and blends of latex is also more of a preference and budget choice rather than a “better/worse” choice and any type or blend of latex is a durable material relative to other types of foam materials. There is more about the different types and blends of latex in post #6 here and more about how Dunlop compares to Talalay in general in post #7 here but the best way to know which type or blend of latex you tend to prefer will be based on your own testing and/or your own personal experience.
Different densities of latex are the result of different amounts of air in the formulation, the size of the pincores in the latex, the amount of natural or synthetic latex in the formulation, and the type of latex (Talalay or Dunlop). Higher densities of the same type and blend of latex will be firmer than lower densities. Natural latex is heavier than synthetic latex and Dunlop is denser than Talalay in the same firmness level because of the differences in how it is made so density comparisons between different types and blends of latex aren’t a reliable way to compare their firmness.
I would treat the purchase of an adjustable bed and a mattress as two separate purchases so you can decide which one of each you prefer and make apples to apples comparisons with each of them instead of being locked in to a combination where you may prefer either the mattress or the adjustable but not both (unless of course you would purchase the same mattress and adjustable from the same source if you were buying them separately anyway or you are receiving a discount for buying both that would make purchasing the combination purchase worthwhile for you). If a mattress works well on one adjustable bed then the same mattress will “work” just as well on any adjustable bed.
There is more information about choosing an adjustable bed in post #3 here and the main adjustable bed topic that it links to that can help you choose an adjustable bed based on price vs features comparisons and also includes some retailers that you can use as good sources of information about the features of the adjustable beds they carry and as pricing references as well (in post #6 in the main adjustable bed topic). Of course there are many other sources as well and prices can change on a regular basis so I would also include some internet searching in your research. I would also keep in mind that online advertised prices are often price controlled so make sure you call the stores you are considering to find out their best prices rather than just looking at websites.
In general terms most foam mattresses (memory foam, latex foam, polyfoam) that aren’t more than about 12" thick and most pocket coil mattresses will be flexible enough to work well on an adjustable bed but when you are over about 12" thick then the mattress may not contour to the adjustable bed as effectively. While in general terms thinner mattresses will tend to be more flexible than thicker mattresses and will contour to the adjustable bed more effectively … this can also depend on the specifics of the mattress layers and components. 12" thickness is only a general guideline because some mattresses that are a little more than that which use more flexible materials may still be fine and some mattresses that are less than that may be less flexible and not work as well but 12" is a good general guideline.
Latex is certainly a very flexible material and works very well on an adjustable bed so a thicker latex mattress may contour more effectively than a thicker mattress that uses less flexible foam materials. The most reliable source of information about whether any specific mattress would be a suitable choice for an adjustable bed will be a knowledgeable and experienced retailer or the manufacturer that makes the mattress.
I would also make sure that you find out the specifics of every layer and component in any mattress you are considering (see this article) so that you can make sure there are no lower quality materials or weak links in the mattress and make more meaningful comparisons with other similar mattresses that use the same or similar materials and components in their designs … especially if you are looking at a mattress in the $4500 budget range…
Phoenix