Sorry to get back so late. We're sorry to hear about the difficulty with your model. In all liklihood, the servos were damaged from the flutter. On all models, but especially aerobatic types, flutter is a distinct possibility. Especially on those aircraft with very large control surfaces. The flutter would have damaged the servos as you described. Even the strongest servos would be hard-pressed to withstand the beating a fluttering surface can give.

130-ounce-inches of torque is plenty strong for a wide variety of models. It's the fact that you experienced the flutter, which caused the damage. You can have excellent servo mountings, a good servo arm, slop-free linkages, excellent hinges and hinge line, and still experience flutter.

With a fluttering surface, it would matter little whether the servo had metal or plastic gears. The flutter could destroy either.