I don't think it's stick sensitivity. I've flown with my all of my sliders all the way up at the top for years, and am convinced it works the best for me. At this setting, 10% stick throw=10% control surface movement, 50% stick= 50% control surface movement, and 100%= 100%. To me, that makes the most sense.
As to the spin, I'd say it would be a good idea to hit the TA and intentionally get yourself into some, just to fix them again. The basic formula for spin recovery is to lay off the ailerons and rudder (neutralize them), and get your nose down (down elevator). Once your nose is down, apply rudder opposite the direction of spin, until the spin stops and simply becomes a dive. Dive a second or two more to pick up some speed, and gently pull out. If you try to pull out of the dive too quickly, you'll probably throw it back into the spin, but maybe reverse the rotation.
MtnMan