Hi bobsbarricades,
“Support” is also often misunderstood and many people believe incorrectly that “firmer is better” or “more supportive” when the real goal is to keep the spine and joints in good alignment in all your sleeping positions and this requires the type of contouring support that allows some parts of the body to sink in more and some parts of the body to sink in less to keep your spine and joints in good alignment and this will vary on an individual basis. This is especially important for those that have back issues. There is more about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress in post #2 here and in post #4 here that may also be helpful in clarifying the difference between the different types of “support” and “pressure relief” and “feel”.
There is some information about the benefits of inclined sleeping where the whole bed is inclined in this topic and in this topic that may be helpful.
Innersprings will tend to be softer and more contouring and resilient than natural fibers. They will also maintain their resilience more compared to natural fibers which can pack down and compress over time and become firmer.
The better options and possibilities I’m aware of in the Jacksonville area (subject to the quality/value guidelines here) are listed in post #7 here but you would need to call them to find out the specifics of what they have available because I don’t know whether any of them would have mattresses available that meet your specific criteria and I don’t know of any that gin their own cotton.
Phoenix