I just finished setting up the control throws on my 28% WH Extra 300LX and I use a homemade protractor-like tool to measure the degrees the surface is moving. On the elevators, to continue with your example, I am using the hole 1-1/4" from center on the servo arm and the length of my control horn is 1-1/4" from the hinge-line to the center of the pivot point. This gives the elevator pushrods perfect geometry...the pushrod is 90 degrees off the servo arm and the line between the servo arm pivot point and the hinge-line on the elevator.

I can get 60 degrees of throw giving it everything I've got. I am going to set 45 degrees up and 50 degrees down elevator in the 3D flight mode. That gives it a little buffer before the elevator hits the stops.

From setting up the geometry on helicopters, it is extremely important to have the pushrod 90 degrees to the servo arm and the control horn. This is not possible on the ailerons on the 28% WH Extra and get the recommended high rate throw.

Edit: It is only off by a little bit, but that's rough for us perfectionists.