Hi cinn,
I think the comments I made in my reply here would apply to your questions here as well.
Your doctor is giving you some guidelines that aren’t specific enough to use to buy a mattress and I would doubt that he knows as much about mattresses as he does about medicine or he would realize that there are hundreds if not thousands of mattresses that would meet the very generic criteria he is providing and they may be so different from each other that some of them might work well for you and some may not be suitable for you to sleep on. Some mattresses that are different from the criteria that he is suggesting may also be a perfect “match” for you in terms of PPP. I believe that you are also becoming much too involved in mattress specs that won’t tell you anything about whether a specific mattress is suitable for you or not and will likely overwhelm you with their complexity.
Nobody else can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved for someone else to really know which mattress may be the most suitable for you based on “theory at a distance” or mattress specs or provide anything more than general guidelines rather than specific ones (see mattress firmness/comfort levels in post #2 here).
You may be making this much more complex than it needs to be and I would follow the steps in the tutorial post rather than trying to design your mattress ahead of time and then trying to find the specific mattress you have designed out of all the many thousands of mattresses that are available and which may not even be possible to find.
Phoenix