Hi MikeK,
The first place I would start your mattress research is post #1 here which has the basic information, steps, and guidelines that will be most helpful to you.
Post #2 here (centered on Huntsville) has a list of the better options and possibilities that are in reasonable driving distance that I’m aware of (this includes a search around Florence as well).
I can certainly understand the hesitation with ordering online because of the additional risk involved in choosing a mattress that you haven’t tested in person and I would always start your research with local manufacturers and/or retailers. If you did decide to go in the direction of an online purchase though … having independent layers which you can choose individually is a way to lower the risk of an online purchase and allows for flexibility of design before and after a purchase so you can use your sleeping experience as a testing ground and fine tune the mattress based on your actual sleeping experience. Latex is very “sticky” and doesn’t shift when it is inside a tight fitting cover and shifting isn’t an issue in normal use. Even if you move the mattress on its side and the layers do shift, it only takes a minute or two to unzip the cover and “wave” them back into position.
Phoenix