I just drill a hole thru the white plastic ball-socket head & screw a long enough 3mm bolt right into the locking collar, keeps everything from twisting for a positive shift.
This works especially well in my 6wds where the trans is raised an inch above the frame, making the shift shaft quite a ways above the shift rod.. using a much longer bolt & a lock nut to secure the long bolt tightly to the plastic ball-socket head, screwed right into the lock collar on shift shaft.
Your idea looks pretty trick Izzy.