Hi LC,
Benstar has already provided the link to the Atlanta list (thanks Benstar :)) so you have some good options to test different mattresses.
There is also more information in post #13 here about the most important parts of the “value” of a mattress purchase that can help you make more meaningful comparisons between different mattresses.
Post #6 here also has more about the pros and cons of memory foam vs latex but the choice of materials will really be a matter of personal preference based on which one your testing indicates you tend to prefer.
Phoenix