Hi Ari,
There isn’t an exact answer to your question, as overall comfort is not only determined by all of the layers contained within a mattress, but also the density, ILD, style of foam, compression modulus, layering and thickness of the layers used, among other things.
In general, the thickness of a mattress is just a side effect of the design and by itself isn’t particularly meaningful because whether a thicker or thinner mattress would be better or worse for any particular person will depend on the specifics of the materials (type, firmness etc) and on all the other layers in the mattress. Thickness is only one of many specs that are used to make different mattresses that perform and feel differently and that makes a mattress suitable for one person and not another. There is more about the effect of thickness in post #14 here. Regardless of how thick or thin a mattress may be … the most important part of the “value” of a mattress is how suitable it is “as a whole” for your particular body type, sleeping positions, and preferences in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) regardless of how thick it may be.
The main benefit of a thicker mattress is that it can be more adaptable for heavier weights and multiple sleeping positions. It will compress from softer to firmer more gradually which means that there is more “range” of compression without the mattress becoming too firm for heavier weights (or parts of the body).
Thickness and softness work together and because thicker layers (or mattresses) can have a greater range of compression and are more “adaptable” … it’s also possible to use firmer top layers in a thicker mattress and still have good pressure relief because of the greater range of compression of the thicker mattress which can create a mattress with a firmer “surface feel” but that still provides good pressure relief and adapts well to the body contours.
One other benefit of thicker component-style mattresses that have multiple layers that can be rearranged or exchanged is that there are more layering combinations possible for changing and fine tuning the performance and feel of the mattress but in many cases this wouldn’t be necessary and in some cases can lead to a level of complexity that can make predicting how the layers interact more difficult (see post #2 here. )
So the overall thickness of a mattress that is either “needed” or “preferred” would depend on the combinations of the layers and components that are needed to achieve the design goal of the mattress and provide the PPP (Pressure relief, Posture and alignment, and Personal preferences) that can best match each person and their unique body type, sleeping positions, and preferences.
While knowing the specs that can affect the quality and durability of the layers and components in a mattress is always important … unless you have a great deal of knowledge and experience with different types of mattress materials and components and their specs and different layering combinations and mattress designs and how they combine together and can translate them into your own “real life” experience that can be unique to you (which would generally be a very small percentage of people) … I would agree and tend to avoid going the DIY route and avoid using complex specifications to try and predict how a mattress will feel or perform for you. When you try and choose a mattress based on complex combinations of specs or only based on specs for single layers or components that may not be as relevant or meaningful as you believe it is then the most common outcome is “information overload” and “paralysis by analysis”. Even the best mattress designers in the industry are often surprised at what a mattress they design “should have felt like” based on the specs when they design it and what it “actually feels like” when they test out their new design. I would instad tend to rely upon the recommendations from knowledgeable manufacturers or layering combinations that have been shown to work well together. Ultimately, the only way to know whether any specific mattress design or combination of layers and components is a good “match” for you in terms of comfort, firmness, and PPP with any certainty will be based on your own careful testing and/or your own personal experience when you sleep on it
Did you have an actual phone conversation with them, or simply submit an email to them? I’d recommend a detailed phone conversation with any business or manufacturer you’re considering, as you’ll be best able to receive the largest amount of accurate and specific information in the shortest amount of time.
No, they have polyfoam for support cores up to at least 40 ILD.
Phoenix