I am going to add one thing I haven't seen mentioned anywhere here. While yes, you can play with controls, or droop the elevator to help equalize a turn rate, or fix hunting, etc. the other 900lb gorilla that can sneak up on you if care about such things is differential turn quality even though the rate is now feeling more equal.
Bear with me here... but if the elevator is drooped a 1/4" or whatever you end up with, you must also have moved the flaps 1/4" the other way with regards to delaying when that flap will add camber to the wing in the other direction. This sensation drives me a bit batty in certain spots... (So now you have a clean pullout with no hint of stall on outsides, but now your insides could potentially mush or stall a little, or visa versa, depending on which way you played with your pushrod)
I "think" we are better off fixing geometric thrust line issues with other means, either thrust line (engine shim) or stab incidence (if a take apart or still in the build phase).
I may be all wet, and I certainly don't have the aerodynamic schooling chop's of others here, so I'll bow to their greater knowledge, but this is at least how I currently understand the situation and putting it into practice has worked very well for me.
EricV
To get an accurate read on whether you are getting a good perception of equal insides and outsides you have to set your neutral with the handle grip straight up and down. If you have a slanted pistol grip handle, replace it with a vertical grip handle. Then fly the model and assess the condition. Your hand now will have more equal leverage in up and down motion, and you can more accurately perceive any turn bias.
If bias is detected, lengthening and shortening the pushrod length between flap and elevator horns will balance out the turn reactions.
Good luck.
Chris...