This is a picture of the pull-pull elevator servo installation. I mount the servo side ways to get best alignment and equal servo throws on the up and down side of the elevator. The servo mount is 1/4" glassed end grain balsa on a 1/8" plywood plate. I use #4-40 soc. hd. cap screws and blind nuts with 1/8" ply reinforcements on the pipe floor plate. Check to see if you have pipe floor deflection when using the servo. If yes, then add pipe floor reinforcement near each end of the ply mount.