To start:
Both elevators must be hinged at exact same centerlines
Both control horns must be at same height from hingeline
Both must be at same vertical from hinge line
both servo arms -same angle on output arm
both servo set for same travel.
with power on radio , move both elevators to center position .
adjust only push rod length to obtain center .
move with power to desired full up /down.
write down difference noted.
If one side moves further both ways , lengthen that side control horn (threaded type best )
if one side moves further in only one direction-- move control horn forward or back (bend slightly) OR move servo arm one spline forward or back (this makes big difference!)
Once you have established that the mechanical setup is as close as possible ,make minor adjustment on Tx throw/sub trim/center
Note that any change in Tx is always interrelated --that is --each adjustment affects other adjustments
change of center affects relative throws.
Please use lower case on your postings -It makes them easier to read .