RE: How sensitive?
cjposada,
When you do a CG adjustment rearward, you want to do it in very small increments. I work at 1/16" at a time until I find the sweet spot, then back a bit more until I don't like it. Then I'll shift forward until I hit that sweet spot again and I know its dialed in. You'll know real quick if you go too far back. A 1/4" jump could end up getting you into real trouble as some planes are very sensitive to CG changes.
As far as elevator sensitivity, it depends on your individual plane. I've flown two different planes of the same make and model, and they both handled differently. The only way to know is to follow what I said above and slowly move the CG back until you don't like it, then forward a bit.
Hogflyer