Hi scurve,
There is a lot of information there so I would read it like you would a good book rather than “study” it like you would a textbook. As long as you know enough to recognize when someone “knows their stuff” and is talking about and understands materials instead of marketing stories then you will be fine.
There are still some firm memory foam mattresses available but they will typically have thinner layers of memory foam … often 5 lb density like the old Tempurpedics. They will also be less costly than softer memory foam mattresses that use thicker layers of memory foam.
Latex and memory foam are not really comparable (see post #2 here) and what works well for you with one material is not a good guideline for what may work well with the other. Your own careful and objective testing is by far the most reliable guideline in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) compared to using any comfort specs as the basis for a choice. Specs can tell you about the quality and relative durability of a mattress but will tell you very little about it’s feel or performance and in many cases the “comfort specs” of the materials in a mattress (such as ILD) aren’t available or particularly meaningful anyway.
Comfort is also very subjective and the Eclipse has a relatively thin 2.5" layer of firmer 5 lb memory foam and for many people it would be a firm mattress but this would depend on the specific characteristics of the memory foam (which can vary widely even in the same density) and on the ILD/IFD of the support layers below it which I don’t know.
If a mattress is “soft” or “firm” to you and that’s how you perceive it … then that’s what it is for you … regardless of how it may feel to anyone else. There have been people on the forum who have been convinced that even 40 ILD latex is too soft for them which I can’t personally imagine and for the large majority of people this would be unsleepable. The old tempurpedic beds took longer to warm up and were more dependent on temperature so they may have felt firmer until they softened with body heat or in a cooler environment.
Phoenix