Hi MikeM,
A single 6" layer would act slightly firmer (when it was compressed more deeply) than 2 x 3" layers. The difference would not be really significant and has to do with the slightly different internal forces (such as shear forces) and resistance between the two layerings. Multiple layering would be more noticeable in the comfort layer (such as 3 x 1" layers of 22 ILD vs 3" of 22 ILD with the multiple layers acting as a thinner/softer surface than the single layer). Bear in mind too that Dunlop has more variability in ILD across the surface than Talalay and also has a slightly “firmer” side and a slightly “softer” side which can also make a small difference. Trying to get to an exact ILD is usually not really possible although Talalay is usually more consistent and “closer” on average to a specific number.
Latex is somewhat unique because it gets firmer faster than other materials (Dunlop more than Talalay even) so a layer that is rated at a softer ILD with 25% compression can still be firm and supportive at a deeper compression. Having said that though … I would tend to be just a little wary with a soft dunlop under the soft Talalay as your hips may sink a little further down into the mattress than you would want for good alignment even though the sinking into the top layer for pressure relief was fine. Your personal testing though would be the most accurate way to know for sure.
There are several high quality Dunlop Latex manufacturers who make 100% natural Dunlop latex. The most common are Latex Green, Latexco, and CoCo Latex (Savvy Rest supplier) and Arpico. Latex Green and CoCo latex both produce organic latex as well (the same material as 100% natural latex but the latex cultivation and production methods have been certified as organic). There is currently no organic Talalay latex even though there is 100% natural Talalay. They all produce high quality molded Dunlop cores that are very comparable however different Dunlop producers will each have their “secrets” in their formulations and production methods. There are many other quality Dunlop producers besides these as well however these tend to be the most common.
This depends to some degree whether you are buying bare latex layers, the thickness of the layers, special pricing that may be in effect, and shipping costs if any. Often the lowest cost is from a local manufacturer who is willing to sell you a latex layer even though many of them are not set up to ship across the country so only supply locally. Sometimes some outlets may have specials with limited selection which may be less.
The better sources for latex layers of all types that I’m aware of are listed in the component post here.
In terms of buying a mattress as opposed to individual latex layers … There are so many different factors and preferences involved that are important to different people that a “price per inch of latex” comparison is fairly meaningless and the best value for any individual could be from any of the members of this site or others that aren’t depending on the features and choices and options that are part of what each person considers important in their idea of “value”.
There are other outlets that may have special pricing from time to time and there are also some online outlets that I don’t fully trust will ship you what you order (such as some on ebay or FBM) both of which may be “cheaper” but you take the risk of buying latex which is either the wrong material or the wrong ILD.
There are currently 2 primary manufacturers of Talalay latex which are Radium and Latex International. I consider both of these to be very high quality. There are also now Chinese and other Asian Talalay latex core producers (at least 3) … some of which may be appearing in mattresses in North America. I haven’t had enough feedback and they don’t have enough real life market experience to know how they compare, especially because most manufacturers are still using LI and Radium.
Hope this helps … and I’d be curious to hear about your experience with M(Dunlop) S(Dunlop) S(Talalay)
Phoenix