Unless all things are equal and it’s a perfect model airplane world any effort expended to align the servo arms perpendicular to the servo case and or parallel to the hinge-line are meaningless. As previously noted it’s paramount to realize equal servo angle or arm rotation and again equal surface throw or travel arcs. It’s highly unlikely both of these travel arcs will be of the same volume due to the linkage geometry associated with unequal servo arm and control arm length at the very least.

Remember sub-trim on modern computer TX’s does NOT affect the ATV travel volume either side of center, however trims adversely lengthen and or shorten travel arcs.

Before you ever get out a TX, Hitec Programmer, MatchBox or the like mechanically matched surfaces i.e., dual elevators are a prerequisite for the elusive matched control throws. Once you introduce offsets in ATV/end-point values (TX’s/MatchBoxes) a scalar relationship with the TX and surface are all but lost.

More common than not; multiple linkage ratios are skewed thus creating unequal surface travel arcs and speed with control arm pivot points not being centered over the hinge-line, miss-matched physical locations associated with servo mounting heights, control arm height, and or control arm mounting locations require that the servo arm be centered wherever required to realize the center of the surfaces travel arc. In nearly all cases the servo arm will be centered several degrees aft with the proper mechanical setup realized of a perpendicular axis pushrod setup (typical of ailerons) and then there is a short pushrod configuration typical of servos in the fuse sides for elevators.

Bob,

If you’ll post the dimension information of the specific elevators, servo arms, control arms, control horn locations and such I’d be glad to run math that will net a nearly perfect initial setup.