Both of the trainers I have, a sig Senior and PT-40 Have quick connects on the servo horns and metal clevices on the control surfaces. I would definitely reccomend some blue loctite and an inspection after every few flights. I hold them with a needle nose and check for tightness when I get home from the field, right after cleaning up the plane.

If routine maintenance isn't in your schedule definitely go with a z-bend, unless the horn breaks it can't come out