Hi baddog,
I would agree with djgoldb’s comments that there is no inherent reason to use only latex if a combination of memory foam and latex (with the memory foam under the latex) works best for you in terms of PPP.
[quote]I now have the following pieces of latex:
6" ILD 44 Dunlop (SleepOnLatex)
3" ILD 30 Dunlop (SleepOnLatex)
3" ILD 20 Dunlop (SleepOnLatex)
2" ILD 21 Talalay (Arizona Premium Mattress)
2" ILD 22 Talalay (Foam Factory)
1" ILD 22 Talalay (Foam Factory)
I also have the following pieces of memory foam:
3" 5lb Aerus memory foam (MFC - Memory Foam Comfort)
1" 5lb Aerus memory foam (MFC - Memory Foam Comfort)
I have tried every configuration/combination of latex, or latex with memory foam but I have been unable to achieve a proper balance between pressure relief and spinal support with my current layers. Memory foam as a topper did not work for me as I eventually sink into it and my spine comes way out of alignment. Memory foam under latex does help but I am trying to assemble a complete latex solution.
It takes at least 5" of soft (ILD 21/22) Talalay latex to completely remove all pressure points and firmness from my hips and thighs, and this only works when on top of the 3" of ILD 20 Dunlop. This is obviously is less than ideal for spinal alignment.[/quote]
Part of the issues you are having may be related to the two latex layers that you purchased from Foam Factory which are almost certainly in a higher ILD range than you believed you were purchasing. There is more about purchasing from Foambymail (aka FBM and Foam Factory among others) in this post and this post and this topic (about their polyfoam and sources) and this post (presumably from a past employee). They don’t sell Talalay latex … they only say they do … and I also wouldn’t consider their latex ILD ratings to be accurate or reliable.
I would probably treat the two Dunlop layers you purchased from them as being in a medium firmness range (@30 ILD or so although this would strictly be guesswork) and use them deeper in the mattress to see if this makes any difference although it can be much more challenging to build a DIY design when two of your layers are an unknown firmness so trial and error will become much more important than their actual listed ILD ranges.
Your design is too complex and has too many layers (including two unknown layers) to be able to predict the types of changes that may be helpful with any specificity but it may be very helpful if you could list your “top 3” configurations along with a more detailed description of your symptoms and sleeping experience on each of them and how they differ from each other (again in terms of your actual “symptoms” and sleeping experience) which may help to identify any “patterns” that can point to the type of changes that may bring you closer to your ideal design.
I would keep in mind that the ILD isn’t a reliable indicator of the relative firmness of memory foam compared to other materials because ILD/IFD testing with memory foam produces completely different results than the same ILD/IFD testing with more resilient foam materials (see post #34 here) and ILD by itself (or IFD in the case of polyfoam or memory foam) is also only one of several specifications that can affect the sensation of softness or firmness relative to different body types and sleeping positions (see post #4 here).
Phoenix