Learn to fly the plane with rudder. Full scale airplanes do not normally use any additional down or right thrust. I quit building in offset thrust years ago, and have become a better RC pilot. If you feel that you must use right and down offset, 2 or 3 degrees is a good place to start. Again, if you will learn to fly with the rudder and learn throttle management, you won't need it.

Bill, AMA 4720
WACO Brotherhood #1