Hi melo,
The tutorial post includes links to several articles or forum posts you can use as guidelines but the information and links that are included in the durability post (post #4 here) would really be all you need.
I would treat all latex as a good quality material relative to other types of foam materials such as memory foam or polyfoam (you can read more about the different types and blends of latex in post #6 here) and for a one sided mattress I would use 4 lb memory foam (or gel memory foam) and 1.8 lb polyfoam as good minimum density guidelines (outside of about “an inch or so” of lower quality/density materials that will have little effect on durability).
4 lb gflex gel memory foam is a medium quality/density memory foam (it’s 4 lb or higher memory foam) and it would be suitable for most weight ranges although if you were in a higher weight range I would minimize the use of 4 lb memory foams and lean towards higher density memory foam (regardless of which manufacturer you were considering).
If you are testing mattresses locally then your own personal testing and experience is the most effective way to compare the “feel” or performance of other mattresses compared to the Tempurpedic Supreme but I would suggest using a common set of standards to evaluate each mattress rather than trying to use one mattress as your reference point which would make your comparisons much more difficult and subjective/inaccurate (see post #46 here).
You may be making this unnecessarily complex or technical and I would focus on your actual testing and experience to decide on which mattress is the best match for you in terms of PPP and make sure you know the specifics of all the layers so you can compare them to the guidelines to make sure they don’t have any obvious weak links and so you can make more meaningful comparisons between mattresses.
The most important part of the “value” of a mattress purchase is how good a match it is in terms of PPP. No matter how good the quality of the materials … if it isn’t a good match for your body type, sleeping positions, and preferences it would have little value to you if you can’t sleep on it comfortably.
The next most important part is to make sure that the mattresses that work well for you don’t have any weak links in terms of quality/durability. If a mattress is a “perfect match” for you but uses lower quality materials and is only likely to last you for a few months or a very few years or the useful life doesn’t reflect the price you paid then it also wouldn’t be very good value.
After these two … I would consider how the mattress compares to others that are similar and the other parts of your personal value equation that are most important to you to make your final choice between your finalists.
For reference … the Tempurpedic Cloud Supreme uses 2" of 4.1 lb memory foam over 2" of 5.3 lb memory foam over a 7" polyfoam base layer. This may give you some sense of comparable mattresses but I would keep in mind that different versions and firmness levels of the same type of foam can be different from each other so while a mattress that uses the same or similar density materials would be fairly equivalent in terms of quality/durability … it may not feel the same and this is the part that you need to test.
This may be what he uses in his mattresses but latex comes in a much wider range of firmness levels from the low teens (or sometimes even lower) to the high 40’s or 50’s depending on the type or the manufacturer of the latex.
Phoenix