I used D-sub pins and sockets staggered to make the trim servo removable.
Cover the now connected wiring with some expandable sleeving and heat shrink.
The hole on the elevator spar that the wiring goes through also conflicts with the threaded rod that sticks out on the servo. I drilled a smaller hole above that large hole big enough for a small snap bushing sized for the sleeved wiring. I made the new hole close enough to the existing hole so I could cut a small slot between the two holes so that the servo wire could be slipped into the new hole from the existing larger hole.
Picture this (rotated 90 degrees):
(crude ASCII drawing representation of big hole and small hole connected by a small slot)
Simply slit the small snap bushing with a utility knife so you can install it over the servo wire then snap it into place in the new smaller hole you drilled. The snap bushing fills the new hole and the slot is small enough to not affect the stability of the snap bushing to stay in the wiring hole.
Once you get the servo installed in the elevator, you can pull the wiring back into the fuselage and make a service loop there for the excess wire.