Why two elv servos
I have a Super Skybolt with two elevator servos mounted just forward of the tail on the fuse sides.
The center of the servo (where the horn screw is) is in line with the last hole of the control horn on the elevator. One pushrod goes up to the horn on the elevator the other goes down.
One pushrod is at the top of one servo and the bottom of the one opposite so they each travel the same direction and also move each half equally.
I, also, was concerned with equal movement of each half and with my servos mounted in the way described they move equally.
I painstakingly measured each one and they move the same on low and high rate, and throughout their travel.
Tom