You want to try to setup the servo mechanically so that you can set your ATV at 140. This is not to get maximum torque, its to take advantage of the maximum resolution. The way I understand it, in most systems there are 1024 steps in the resolution of the transmitter. If you setup the servo linkage so that you have to dial down the ATV to make your maximum desired throw you are proportionally reducing the resolution which makes control less precise.

It all plays into the geometry of the setup. You want to setup your geometry to get maximum mechanical advantage (torque) where you want it, for me thats the desired max throw you want on your highest rate (ATV) and be able to set yout ATV at 140. Personally I set my transmitter at 140ATV and then adjust the throw mechanics until I get the max throw I by adjusting the pushrod length and control horn/servo arm adjustments. Try to get as close in on the servo arm, and far out on the control horn as I can get it and get the throw I need.