Hi Nola,
Most of the PLB stats are in post #4 here.
The specs of the Serta Respite are here.
As you can see (and probably already know), and assuming that the convoluted foam is at least 1.5" … there is at least 2.5" of polyfoam and some synthetic fiber over the 2.5" of talalay latex … all of which would be subject to premature softening and compression. This is on top of a polyfoam support core.
If I was going to go in this direction (a talalay latex comfort layer over a polyfoam support core with some softer polyfoam in the quilting but not enough to cause “issues”)… I would probably consider something like this which has 3" of talalay latex (and you can choose the ILD) with 1.5" of polyfoam in the quilting and a 2.35 lb density polyfoam support core (which is higher quality than the Serta) and is selling for significantly less. I know the manufacturer of this mattress and think highly of him and the mattresses he makes.
Custom Sleep Design is a slightly different animal with the zoning however it does seem to indicate that your weight and measurements are somewhat more evenly proportioned and the zoning has less “differential” than the norm. this means that you would likely sink more evenly into a matress. The low profile pillow was likely in deference to your neck issue and the fact that a higher profile pillow on your stomach can aggravate neck issues.
Phoenix