Graydon,
Most of the "experts" I have seen fly use the pinch method, but also practice the thumbs only method from time to time just to keep dexterity optimal. Some people will argue that it takes more brain power and muscle to use two fingers, but conversely, using only the thumbs decreases accuracy....... I however, look at it this way: If I can drive a car using my feet and hands, and play with the stereo, while talking on my cell phone and eating a sandwich, then I should have no problems using one or two fingers on a transmitter...