Originally Posted by jester_s1

I'm not too sure about that one. A tight wood to wood fit is the most important thing for a strong glue joint. Assuming the parts aren't in a bind, opening it up will just require filling the gap with glue. That doesn't ever make for a good build.
It's ok if some glue pushes out. Press it into the wood so it soaks into the pores on both the fuselage and the tail. Wipe off what smears and press it into the joint after it's in place. Clean the residue with alcohol before it starts to cure.