basic building/repair questions
 

1) for pinned type hinges (2 pieces with a metal pin, just like a door hings) we commonly coat the hinge with vaseline where we don't want the epoxy to stick. This way, even if you get epoxy on the part that needs to move, it cracks off easilly.
Note: I said EPOXY. CA is used ONLY for installation of the fuzzy CA hinges.
And... with most plastic pinned type hinges, it is recommended that you drill vertically through the control surface and hinge, (and the fixed surface and hinge) and insert toothpicks to lock the hinge in place. then CA the toothpicks in, clip off excess, sand and cover with a dot of covering material. Even epoxy lets go of the nylon.

2) n theory, yo can use any of the 4 holes... but it is best to use the furthest out, and adjust the throw by choosing the hole on the servo arm which gives the correct deflection angle. (on trainers... usually one of the two the innermost holes.) with the servo arm disconnected from the servo, TX and RX on, set the trim to center, and attempt to adjust the pushrod length for the elevator (or orhte surface) to be centered with the servo arm ftting on the servo 90 deg to the pushrod. (for even travel) For ailerons... with th control horn on the bottom of the win, set the servo arm a bit forward of 90 deg... anywhere from 70 up to where its 45 deg in relation to the pushrod. That wll gve "Differential" throw, making the ailerons move up more than down, and helping revent "tip-stall" in a low speed turn.
fnal trim is always done with a test flight, by an experienced pilot... no 2 planes are exactly the same.

3) Does the covering have a sort of paperlike feel? It may be "silkspan." which is a special tissue paper, panted with "dope." (a fuel resistant paint which shrinks as it dries.) If so... you can get some more of the tissue, and tear out pieces to patch the holes. (torn edges hide easier) You'll need to get the same fype and color of dope... It will be a "Butyrate" based, and the translucent color may be a little hard to find now. :( (Dope was the main paint used n models for about 50 years... Its not as popular for R/C models since the mid 1980's.)