Hi awoogala,
That’s a good thing but your comments indicate that you may not have understood some of the information.
This would be very unusual. While latex is certainly not everyone’s preference and many people prefer other materials better … with the hundreds of different latex combinations and firmness combinations that are possible it would be unusual that someone “couldn’t do it” completely except in terms of preferences (or a type 1 latex allergy which would also be very rare).
As you’ve hopefully read … “very soft” depends on which layers you are talking about (comfort layers or support layers) and is also very relative to the person. The type of mattress you are mentioning will “predictably” break down and soften quite quickly for the reasons you have read about which is why I suggest avoiding them completely and choose mattresses that are just as"'soft" but use better quality materials. A mattress is only as good as the materials in it and so called “high end” mattresses can use some very low quality materials.
“Feel” in a showroom is a very unreliable way to buy a mattress and leaves you very susceptible to the sales training that can manipulate what you feel in a showroom environment. Many different combinations of various materials can match your “needs” for pressure relief and alignment and gel is no different than other types of memory foam or other higher quality foams in this regard. The key is to know what you are lying on and know the materials inside it so you have a much better idea of “why” it performs the way it does.
Unfortunately there is no way to make this comparison outside of “feel” based on your own personal testing. You are not making an “apples to apples” comparison or realizing that you need to compare comfort layer to comfort layer and support core to support core to compare two different mattresses … not everything “lumped together”. Feel, pressure relief, and support are all different “types” or what I call “species” of softness and they are very different from each other. Post #15 here may be worth reading.
If you are able to find out exactly what the materials are in the M7 comfort layers then you could come much closer to “matching” them. Unfortunately they are not likely to be either willing or able to provide this to you. If you had this then at least you would be able to match the comfort layers and you could focus on trying to “approximate” the support core.
I think your fundamental or “baseline” assumptions may not be quite correct and you may be heading in a very difficult or confusing direction until you have a more basic understanding of “why” different mattresses do what they do.
This may be true … but some good local testing with the help of someone that can help you understand “why” different mattresses feel and perform the way they do would still be very helpful no matter what you end up buying. Again I think you may be operating under some flawed assumptions that may make your search a little more difficult and complicated than it needs to be.
Phoenix.