only a suggestion... what if your vertical stab is cocked to the side (IE: Not 90 deg from the hor stab) wouldn't this make for downward pitch when rudder is being used (instead of directing side / side it is acting as a slight elevator)
I dont have much experience with the planes, I have my 1st 4* on the table being built now.
now this would only give down pitch in theory to one direction, and up in the other.
Just a thought to consider...