ELEVON = elevators that also work as ailerons

AILEVATOR = ailerons that also work as elevators

These mixes are used on delta wings and such, but can also be used simply for dual elevator servos. I do this all the time for dual elevator or dual aileron servos with my 9C. All you have to do is:

1. First enable the mix, for example ELEVON
2. Set the Elevator percentages to 100%
3. Set the Aileron percentages to 0%

What you are doing is keeping the elevator function across the two servos, while disabling the aileron function. Good thing about this type of preprogrammed mixes is that trim and offset are adjusted automatically on both servos, while subtrim and end points of the individual servos can be adjusted independently.

Any more detail than that, you'll have to consult your TX manual.