Using the same example: minimum 75 oz of torque needed at the surface, 100 oz/in servo, desired 50 degree surface deflection is met with ATV at 100%:

Say I want to increase the speed of the control surface so I move the horn in on the control arm to .75" with the servo arm at 1" for a mechanical disadvantage (we all did this before at one time right?).

If I did my math right, a 1" servo horn at 100 oz coupled with the .75 control horn will net 75 oz/in. So far I am meeting the torque requirements of the surface. But I will have to dial down my ATV to reduce the now increased surface deflection.

I can see that I lose resolution by dialling down my endpoints (ATV). Also I guess with less throw I won't be getting the full range of available mechanical advantage (re: what mtthomps posted)?

Did I just answer my own question or are there any other negatives of working at a mechanical disadvantage (even when the torque requirements are met)?