So you glued the coupler into the bottom tube instead of the top? What did you do to strengthen the bulkhead in the upper tube?
(This kit is my next build!)
UPDATED: I went back and checked and I actually did use a coupler for the bulkhead and I shoved it up about 10" into the upper section.. I remember Dave sent me an extra one and I cut it short and used the remainder to reinforce the AFT section of the rocket. Sorry for my first answer. The more I thought about the more I had to check.