I have been using a similar system for all sizes of planes fom 0.60 size to 42%'ers for years but I get off the shelf ends from Central Hobbies.

[link]http://www.centralhobbies.com/control_linkage/pushrod3.htm[/link]

A couple of tips for you on the system you are using.

JB weld is definitely recommended over the 5 min epoxy - especially for larger planes

Use a solvent wash on the inside of the carbon tube before gluing, no matter what glue you use.

Make sure the Carbon tube you are using is a very close fit on the threaded rod you are using.