Robert, sounds like you are on the right track. Everything that Dave states as far as CG tests are good points. Rapture. Knowing that full scale airplanes need to have their pitch trim adjusted constantly is where most model pilots get hung up. They see this condition with their models as being normal. IMO getting the CG in the " sweet spot " will allow the model to keep the same pitch trim from 1/3 to full power without any reduction in tracking stability. The end result of this and about a dozen other trimming tidbits gets you a model that not only performs aerobatics well but is easier to fly across the entire envelope.