I use a Z-bend or a plain 90 degree bend with a wheel keeper, at the servo end on most of my planes.
The yellow is my Stick-It V.. and the other my Somethin' Extra.
Neither flutter, and the pushrods can't rotate.
With your surface connections JBWelded in place, that should be good enough.
The "stuff" around the servo would be balsa.
Or if nothing else works, pull the servos, mount them on a large piece of plywood, and then reinstall in the wings.