RE: Fin / rudder misalignment
How about plugging the hole with a balsa plug and a little thin CA. I havent done it with balsa but I have done it with ply, but used epoxy and a dowel. Was able to redrill right on the seam. Only if you're sure you cant move it a little. I've also wallowed out a hole some and filled with epoxy. It worked on a .60 sized plane.
Edwin