RE: Albatros DVa
Can you post a photo showing how the strap hinges are attached/built into the ailerons?
My understanding of how these work is that the hinges are slipped onto a dowel that will become the ailerons (or elevator of rudder) leading edge. The hinge collar rotates freely around the dowel with the strap parts extending forward. The when it's time to mount the aileron's (after everything is covered), it's a simple matter of bolting the straps onto the wooden block supports in the main wing. It doesn't seem like alignment would be an issue since the hinges are aligned by virtue of being built onto/into the flight surface leading edge.
But this may be a different technique than I'm familiar with. BTW, I love the idea of strap hinges and I'll certainly use them on any German model.