sensei

In my own experience with many of my own and others aerobatic aircraft including Extra's, improper C/G has only caused pitch instability issues within those airframes and in turn main lined to nasty snap rolls when pulling on the elevator stick just a tad too much. Crjame expressed that his airplane flies like it is sitting on top of a ball; that it falls off to one wing or the other in roll; he did not express any issues in pitch. That said I would be inclined to look at servo centering, a warped wing or tail surface, incidence issues from one wing to the other and I would also check the horizontal stab/elevators incidence for any issues. These types of issues cause pilots to trim for level flight; the problem with trimming for level flight is these issues are all speed sensitive, so no matter what you do for trim you will always have a constantly changing problem. If one wing is heavier than the other then do what it takes to make them weigh the same because again, you will trim to carry the heavy wing at a given speed and then when you fly faster or slower and now you are back on top of that ball. Just saying...

Bob