Hi pressurepts,
You’ve probably already read this but just in case … the basic information you will need to find your “best” mattress is in post #1 here. This will help you eliminate your worst options (major brands, chain stores, and any mattress where the quality specs are not available or material quality is low) and focus on the better ones (some of which you seem to have visited already). It also has some guidelines that can help you test mattresses more effectively.
Some of the better options in the San Francisco Bay area (including BE which I think are good quality and value) are listed in post #2 here including one which is a member here and carries some very high quality and value innerspring/latex mattresses that can be customized in many ways but would be a bit of a drive away in Santa Cruz.
You have some very good options and choices available in the area.
It certainly could work and as you probably discovered at BE microcoils and latex can be a good combination but you would need to test it for PPP (Pressure relief, Posture and alignment, and Personal preferences) to know for sure. Depending on the design … some mattresses with microcoils may work well for you and others with different designs may not be suitable. If you do some initial research on the phone before you test mattresses (and I strongly recommend that you always call any manufacturer or retailer you plan to visit before going there anyway) you may be able to track down some mattresses that included microcoils in the comfort layers that you could test.
Phoenix