You know the CRs are loose like that because they are machined wrong. What I would have done is use a a couple wraps of tape on the CR line and then put on the CR to butt against tape, which will keep it from moving on you and keep it perpendicular. You can also apply a bead of wood glue to the area. Using "wood glue" run a nice fillet and wipe clean with your finger. Let it set up and then run a fillet along the back of the ring. Did you know the wood glue itself is stronger than the parts being bonded? Epoxy has it's place and normally used for bonding unlike materials. Fiberglass and wood or plastic etc.
You will fit right in this forum where 90% of the people on here over build their projects and end up with a tank. You could build this entire kit with wood glue and get better flights. If you would have used wood glue it would have been easier and less mess and clean up.
Good luck!