Originally Posted by chorner

On mine all I needed to do was do a few trial "dry" fits, and I did have to re-align the hinge holes slightly in a couple cases but for me at least there was no need to add any balsa to any of the individual flaps. Perhaps not all runs are the same (well, I know they aren't... I had a different issue in that the outer flap panel on the right side -the balsa flap- was warped out of the box) but the fibreglass ones should all be pretty close to each other across kits. Before adding balsa etc. I would check they are the same size right to left, and just work on your hinge holes on the trailing edge of the wing/centre section.

One of the things I did on mine to tighten up and get the tips of the flaps "dead on" in terms of lining up horizontally, was to cut thing pieces of solid card stock (or, pieces of glossed servo extension package labels) and you can put a thin even coat of CA to prevent wear. These go on either the underside or top of the metal flap "fingers" depending on whether you need to raise or lower the joining flap a little bit. They tell you in the manual to build up the pocket of the flap with CA, but that's a load of BS. You'd be there for a week trying to mess around like that with the amount mine were off.