Hi GJBenn85,
There’s little I can add to Coventry’s advice except to reinforce that local testing can help a manufacturer help you more effectively. Talking to them will also give you more information about what they offer.
I think a good first step to simplify the process would be to decide on which of the two basic premium foams you prefer between memory foam and latex so that you can exclude one or the other.
I would avoid the tendency to analyze “comfort specs” like ILD and combinations too much because it’s far more complex than most people would really want to know and I would focus more on how you feel about different layers you have tested and let the manufacturers know the specs about which ones were best for PPP (pressure relief, posture and alignment, and personal preferences). In other words I would “report” the comfort specs connected with your testing rather than analyze them. Let them do what they are best at which is giving you good guidance so you don’t have to re-invent the wheel and learn what they have taken years to learn. even then there is much more to a mattress than just the foam and they would know all the smaller details that can affect the performance of the mattress besides just the foam. Your job in other words is to give them good feedback about your needs and preferences based on local testing. Their job is to use your feedback to help you make better choices. Without this they will go by “averages” which is what an average person of your body type and sleeping style would normally prefer.
Regarding latex allergies … post #2 here has more information and helps explain why for the vast majority of people … allergies to latex foam is not an issue.
Phoenix