RE: Mounting dual elevator servos
If your servo arms are both on the center line of the control horn horizontaly. Then it should be fine. Some guys will do this intentionaly if their radio won't mix the servos to run both elev halves. The preffered method would be to put one servo in front of the other on the same plane. Have you thought about using low profile aile servos? They might fit back to back.
David