To answer the basic question, control throws are always measured at the widest part of the surface. The wider part of a surface will move a larger distance than the narrower part. If the instructions call for 1" of throw, and it is set at the narrow end of the surface, the wide end will actually be moving more than one inch. Like it was said earlier, the amount isn't necessarily that critical, and it's best to set dual rates, with the low rate being real tame compared to the high rate, at least for a maiden flight. After you see how the plane reacts, you can adjust to your liking.

Jesse