FWIW, I have standard size ball-bearing capped Futaba 148 servos at 42 oz./inch on the ailerons and elevators (one for each control surface) on my 15lbs Sig Clipped Wing Cub and have had no problems after roughly 25 flights. On the rudder, I used a 65 oz./inch Hitec 545BB servo and the darn thing knife edges very well!