Ray I have used the 85MG in other applications and it is a great little servo! However, with the metal gears it is a heavier servo by quite a bit than say a JR 331 or better yet a JR 241. The rudder input required is quite small and not much torque is needed. You can get adequate mechanical advantage with a short servo arm to preserve the resolution at near 100% travel. Expo helps the most. The lighter the better!

Red