Man, you guys are taking all the fun out of seat-o-the pants ingunerring and Booty fabbing!!!
I'm going with the cotter key method on the rod end. The TRE is absolutely not safe in the current set up with the rotation.
I think the best solution is put this brand new high quality rod end into use and secure it as good as possible (cotter key) and keep an eye on it.
As Mark Twain said...
"Put your eggs in one basket,
and watch that basket very carefully."