RE: Multiple servos for elevator?
A couple of additional thoughts.
It depends on the Tx. If the radio has mixes available, that is the easiest way to accomplish the task IF both channels used have trim available. If trim is not available on both, one side will trim and the other will not. Not an acceptable solution.
The second is, once a way to reverse the servo is determined, another issue pops up. All servos are not created equal. You will need a matched set that moves at the same speed and distance. If you are lucky and start with 4 or 5 servos, you can usually find two that are matched. The alternative is using unmatched servos, where one will move fruther or faster than the other, which results in some strange effects on the aircraft. That is why things like programable servos and Matchboxes are made.
If these are standard or larger servos, and you have the soldering skills, reversing the wiring is not difficult. On some servos it is very difficult because of the physical layout inside. Look inside before you leap. Micro servos are always a pain to rewire.