Hi missy_
I would keep in mind that memory foam that is made by two different companies can have very different properties and firmness levels even if they are the same density and that density has little to do with the softness/firmness of a material (see post #9 here and post #8 here). I would also keep in mind that while it’s important to know the quality specs of the materials in a mattress to make sure there are no weak links and to make more meaningful comparisons with other mattresses … they won’t tell you anything by themselves about the “feel” or performance of a mattress because they are just one small part of a much bigger picture. Focusing on too much technical information or detail can end up leading to “information overload” and “paralysis by analysis” and lead to just as many surprising or “less than ideal” choices as not having enough information about a mattress in the first place.
Having said that … I don’t know the specs of all the mattresses that are in the memory foam list off the top of my head but I do know that Select Foam and Christeli both use 7 lb or higher density memory foam in some of their mattresses. I would also keep in mind that a mattress can also be a close approximation or “equivalent” of another mattress that uses a different design or memory foam density in terms of PPP because of how all the materials interact together.
There are only two ways to know or be able to predict how any mattress may feel for you. One is your own personal testing and the other is a more detailed conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart. They can talk you through the options they have available and are more likely to “educate you” about the options they have and which one is most likely to be the most suitable choice for you instead of just “selling you” anything they can. If you still aren’t confident about how suitable a mattress may be for you after a more detailed phone conversation then I would also make sure you are comfortable with the options you have after a purchase to exchange or return a mattress (and any costs involved) just in case, and in spite of the “best efforts” of both you and the retailer/manufacturer, your own personal sleeping experience indicates that a mattress isn’t as close to your “ideal” as you hoped for.
Phoenix