Hi sparky.
Thanks for your latest update …. I am glad to hear that your sleep is improving 
You are correct that a mattress pad or even a tighter protector …. especially a wool one that will compress a bit more with use can have the effect you are seeking. Most of the wool pads and protectors have stretchy corners or sides so they won’t bunch up while sleeping, but you can look for a tight pad/protector that wraps around all sides of your mattress to add a bit of extra stiffness. Thicker wool layers that are initially soft (and quite frankly nicer) will tend to compress and affect the feel of the layers underneath them over time more than thin ones .… Post #10 here has more information about mattress pads, protectors and the difference between them. Halfway through post #89 here there’s more about the pros and cons of different types of mattress protectors for those who want (or don’t) to affect the feel and performance of their mattress. You may wish to check out some of our members here who have wool pads/protectors and can also have a look at different types of mattress protectors here and here.
I hope this is helpful and I’m looking forward to any ongoing updates you have the chance to share.
Phoenix