Hi shawn.peerless,
Unfortunately there are too many unknowns, variables, and personal preferences and circumstances involved for anyone to be able to suggest which specific mattress or design would be best for you based on either specs (yours or a mattress), health conditions, or “theory at a distance” out of all the thousands of mattresses that are available on the market (see mattress firmness/comfort levels in post #2 here).
Having said that … the mattress shopping tutorial here is the best place to start and has all the basic information, steps, and guidelines that can help you with “how” to choose the mattress that is best for you … and perhaps more importantly know how and why to avoid the worst choices.
With the information that you have provided … it seems that you do better on more resilient materials (such as latex) and perhaps even an innerspring/latex hybrid (such as the Nature’s Spa you liked) because of your need for ease of movement on the mattress. It would probably be a good idea to avoid memory foam in your case because it’s a slow response material that is more motion restricting which it seems could present some issues for you.
As far as what you “should” be spending there’s really no definitive answer to this but I would suggest as much as you can comfortably afford … within reason and within limits of course. You will find better quality and higher performance materials and components and more sophisticated and complex designs in higher budget ranges but once you reach about $3000 or so (in queen size mattress only) then any realistic or meaningful performance benefits that go with higher prices than this may be minimal and there would need to be a compelling reason and obvious benefits for me to spend more than that (again in queen size) and even then I would make some very careful value comparisons based on the parts of my personal value equation that were most important to me. The odds are also good that you will be able to find a high quality mattress in a lower budget range than this that will work very well for you. While it’s not really possible to be too specific about value relative to mattress materials and construction because there are so many combinations and variables involved … this article may give you some sense of the budget ranges that may be worth considering.
I would keep in mind that higher prices don’t necessarily mean a better mattress or a mattress that is more suitable for you.
I don’t have any personal experience with this pillow but perhaps some of the members here have purchased it will see your post and can share their experiences. There is also more information about pillows in the pillow thread here that may be helpful.
If you follow the steps in the tutorial post one by one you will have the best chance of success. If you let me know your city or zip code I’d also be happy to let you know or the better options or possibilities I’m aware of in your area although you may already have found the forum list closest to you since the two stores you visited would likely be included in it.
Phoenix