Hmm,
Not sure about the rudder bellcrank being "unnecessary", although I agreee it could be left out. It's main function is to take the tension of the closed-loop system off the servo bearings, and isolate them in the bellcrank bushing. I don't bother on my sport models, but don't fancy losing rudder on a 1/4 scale plane. (Yes, I know, we all use ballraced metal geared servos etc. !) Don't take this as criticism, I just wanted to clarify why the bellcranks are probably there
I definitely DON'T like using z-bends at this scale either - have replaced all with 4-40 solder clevises.
I'm pondering the rudder retention problem too - would rather it stays put! I plan to slot the carbon tube as suggested, and pin the rudder through it. Just need to ensure it won't bind.
Cheers,
Cam