To get perfect holes... you can make a jig. You can even make a jig set for each model because they are easy to make and cheap (and disposable)

Take a scrap of 1/2 inch X (Y)thickness of surface to be drilled, drill it (in a drill press preferably) centered in the (Y) edge. If its a balsa scrap harden the hole wth CA and redrill.

Glue the scrap to a 2 inch square of 1/8 inch lite ply. ( the punch-out scraps from a 4*60 fuselage make good pieces for this)

you now have a drill jig for use with a "Pin Vise" A Pin vise is the ideal way to drill balsa for Robart hinge points. (power drills tend to rip the balsa) All holes driled with the jig will be exactly the same angle and exactly the same distance fom the edge. (remember to always keep the thing on the same side of the wing or stab...)

**** note... if yuo WANT the hinges offset or angled... you can make the jig appropriatelyand all holes will be lined up.