Hi BGFalcon,
If I was in the area … I would certainly include Country bedding in my research and there has been some good feedback about them in the forum. You’ve probably seen this but just in case some of the other options in the area are in post #2 here
I do know from the feedback of other forum members that their memory foam is 5 lbs, their gel foam is a 4 lb “swirl gel” (which is good quality material and probably GGlex made by flexible foam) and I would guess that their base foam is at least 1.8 lbs or better but this hasn’t been confirmed by any of the feedback yet.
The material itself is really a matter of preference and the suitability is a matter of the design and layering of the mattress. there really isn’t such a thing as one material being “better” than another for a certain condition because any material or combination of materials can be layered in a way that can be suitable for a particular person … and not for the next. No matter what material you prefer though … it will have better and worse quality versions and better quality is more durable and usually a better choice.
Yes it is very unusual and it will extend the life to quite some degree. The key with a mattress like this is that the comfort layers on each side aren’t so soft that they affect support when the are on the bottom and with this one it’s not an issue.
It’s already been confirmed that their foams are made in the USA which would be good enough for me. Many manufacturers prefer to keep their sources private (for competitive reasons) but I would have no issues with their sources.
The only missing piece that I don’t know (and would like to) is the density of the support foam. The rest is in various posts in this thread.
I’m looking forward to your feedback and adding to the knowledge base about what I consider to be a very good option … but can’t talk to in person 
Phoenix