The manual for the MA-10 explains how to set the neutral and end points for each individual servo and end points for paired sets from the matchbox.
No TX magic necessary. When the endpoints and neutral are trimmed to match the travel should be identical.
Right now they are off because one is traveling further then the other.
http://manuals.hobbico.com/fut/msa10-manual.pdf
Wish we could upgrade our 7C's with the 7C 2.4g software.. It can do it on the TX.