Hi Jeff, I know it's against the rules, but I make a sleeve out of glass and carbon fiber, then cut the parts to be connected straight, then epoxy the sleeve in place.
( first dry fit everything and make some jigs to hold the mast in alignment) Once the sleeve is done I prep the outside of the joint and tape up the mast track with "flash tape" ( http://avtcomposites.com/order.php3?i=91 ) not (http://www.herroom.com/braza-1009-flash-tape.shtml ) and vacuum bag on a few (5+) layers of carbon.
I have done this more then a few time and never had a problem. (yet!!)


Best of luck.
les