RE: SONIC 500
Delta,
Mixing bad habits out of racers is normally not done much at the higher levels. Most racers frown on mixes as they do create additional drag.
Normally, changes in thrust, wing incidence, CG, and lateral balance are enough to take out all bad habits of the current racing planes. One of the biggest issues with the faster planes is how it comes out of a full pull on turn #1 or even a hard turn around #3 while on 90 degree knife edge. Some planes will want to tuck (continue rolling over through the turn), or balloon (roll back out of knife and climb).
These can be mixed out pretty easily with a little left or right aileron slaved to the elevator, but it is not really fixing the problem of one wing being heavier than the other. If the tuck or balloon is minimal, I will normally mix it out, but the real fix should be adding weight to a tip.