Oh, well that changes everything. On the PT-40, set up some aileron differential to fix the adverse yaw problem. You can do that very easily with one of those 6 armed servo horns. Make a "V" pointing away from the linkage to the ailerons and fix your pushrods to make the ailerons straight with the bottom of the wing again. That will give you more up throw than down which should eliminate most if not all of the adverse yaw. This is a much better solution because to mix rudder in that plane is also going to give you some roll coupling which you'll have to correct for.