Flap Alignment

On models where the flaps are epoxied onto the hinges after the finishing process, how do you ensure the flaps are perfectly aligned with each other? You can't sight down the T.E. because the fuselage is in the way.

You can sight from the rear of the fuselage and be fairly accurate.

I put an ink line centered through the wing cutout on both fuselage sides before installing the wing. I then make sure my flap fillets are centered on this line when I install them. After the model is finished and I am ready to install the flaps I just align them with the flap fillets and I know they are even.

If I forget to mark the fuselage before I install the wing, I level the wing on my work bench and use a height gauge I made with a pen to mark the fuselage sides.

I use an incidence meter.