Hi foofooboopeep,
If you are attracted to the idea of designing and building your own DIY mattress out of separate components and a separate cover then the first place I would start is by reading 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).
There is also 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” and “pressure relief” and “feel” that may be useful as well.
For those who decide to take on the challenge then I would either 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 comfort, firmness, and PPP as a reference point or blueprint and try and “match” every layer and component in your reference mattress as closely as possible or use a “bottom up” approach (see post #2 here).
If you are near the Chicago area then the better options or possibilities I’m aware of (subject to making sure that any mattress you are considering meets the quality/value guidelines here) are listed in posts #2 and #4 here. I would certainly suggest a visit to My Green Mattress/Quality sleep if you are in the area.
Each mattress category can include hundreds of different mattresses with a very wide range of different designs, different “feels”, different characteristics, and different firmness levels. Every individual layer and component in a mattress (including the cover and any quilting material) will affect the feel and response of every other layer and component both above and below it and the mattress “as a whole” so each mattress category will generally include some mattresses that have a design that will be a good “match” for you in terms of “comfort”, firmness, and PPP and others that use the same type of materials and components and are in the same category and may be just as durable but have a different design with different layer thicknesses, different types or blends of latex, of different firmness levels for each layer, or a different cover that may be completely unsuitable for you to sleep on … even if it uses the same general type of materials and components.
The designs of the mattresses you tested are different than the 3 x 3" mattresses that you are looking at (they have different layer thicknesses and possibly use different types and blends of latex and different firmness levels for each layer as well) so you won’t be able to “duplicate” the mattresses you tested and all I can say for certain is that they will be different to some degree from the mattresses you tested.
When you can’t test a mattress in person then the most reliable source of guidance is always a more detailed phone conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart and who can help “talk you through” the specifics of their mattresses and the properties and “feel” of the materials they are using (fast or slow response, resilience, firmness etc) and the options they have available that may be the best “match” for you based on the information you provide them, any local testing you have done or mattresses you have slept on and liked or other mattresses you are considering that they are familiar with, and the “averages” of other customers that are similar to you. They will also know more about “matching” their specific mattress designs and firmness levels to different body types, sleeping positions, and preferences (or to other mattresses that they are familiar with) than anyone else.
I would also make sure that when you are buying a mattress online that you haven’t tested in person that you are comfortable with the options you have to exchange or return a mattress (or in some cases individual layers) and any costs involved just in case your choice doesn’t turn out as well as you hoped for because the only way to know for certain whether any mattress will be a good “match” for you in terms of comfort, firmness, and PPP will be based on your own careful testing or your own personal experience. As far as I’m aware Mattresses 24/7 doesn’t have an exchange or return policy so there would be some risk involved in choosing a different combination of layers that aren’t the same as a mattress you tested.
Since you don’t know the specific type and blend and firmness level of the layers in the mattresses you tested it would also be very difficult to know for certain which combination of layers would be the closest match or approximation but whether you choose a layering combination that Val believes would be closest to the mattress you tested or choose the layering combination that she would normally suggest for someone with your body type and sleeping style based on the “averages” of other customers that are similar to you would depend on your confidence that the mattress you tested was a good match for you in terms of “comfort”, firmness, and PPP and also your confidence that the layers she is suggesting would be similar to the mattresses you tested and on your risk tolerance as well.
Phoenix