Hi LookingNow,
Thanks for the feedback on your “mattress surgery” and I hope that it works out well for you. You’ve probably read this already but there is more information about the mattress surgery process in post #2 here and the posts it links to.
Unfortunately I can’t make any specific suggestions or recommendations because you are the only one that can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved that are unique to each person to use a formula or for anyone to be able to predict or make a specific suggestion or recommendation about which mattress or combination of materials and components would be the best “match” for you in terms of “comfort” or PPP (Posture and alignment, Pressure relief, and Personal preferences) or how a mattress will “feel” to you based on specs (either yours or a mattress) or “theory at a distance” that can possibly be more accurate than your own careful testing (using the testing guidelines in step 4 of the tutorial) or your own personal sleeping experience (see mattress firmness/comfort levels in post #2 here).
There is more about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress in post #2 here and in post #4 here that may also be helpful in clarifying the difference between “support/alignment” and “pressure relief” and “feel” that may also be helpful in the trial and error process of choosing combinations of materials that will work best for you. You appear to already have a good support system (your pocket coils) so it will be a matter of experimenting with the foam layers that you use on top of the springs.
Since mattress surgery is similar to building a DIY mattress … I would also read read option 3 in post #15 here and the posts it links to (and option #1 and #2 as well) so that you have more realistic expectations and that you are comfortable with the learning curve, uncertainty, trial and error, or in some cases the higher costs that may be involved in the DIY process. While it can certainly be a rewarding project … the best approach to a DIY mattress is a “spirit of adventure” where what you learn and the satisfaction that comes from the process itself is more important than any cost savings you may realize (which may or may not happen).
I would also tend to use the specs (if they are available) of a mattress that you have tested and confirmed is a good match for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) as a reference point and try and “match” them as closely as possible or use a “bottom up” approach (see post #2 here).
I would also keep in mind that a mattress that works perfectly for one person may be completely unsuitable for you to sleep on so I would prioritize your own experience on each combination of materials and components to help you decide on any additional changes to make in your design rather than using other people’s experience which may be very different from your own, Each person is unique.
Foam manufacturers don’t provide information about the specific combinations of chemicals they use in their foam formulations which are proprietary so the only way to assess whether a material may be “safe enough” for you would be based on the certification it has and the testing limits for each chemical they test for. There is more information about this in the previous posts I linked but I would always keep in mind that some people that are very sensitive to some materials may still be sensitive to a specific foam that would be “safe enough” for most people but you may not ever be able to find out the specific ingredient in the foam that you are sensitive to that is the cause of your sensitivity so it doesn’t necessarily follow that if you are sensitive to some memory foams that you will be sensitive to all memory foams (or any other foam material).
It may be helpful to ask for a sample of any foam you are considering using so that you can use it to get some idea of whether you would be sensitive to that particular type of foam.
Phoenix