Richard,
Re-consider using the side hatch. After you are done painting it can be covered with a small piece Monokote... no one will see it when it's flying. As far as the stab/elevator, Glue in the stab with the elevator control horn loose. Fit the top blocks and vertical fin then glue them in place. Then glass and paint the fuse, stab and fin all at once. After you glass and paint you can then hinge and attach the elevators which will hold the elevator control horn in place and Bob's your uncle.
Thom