Oh, one other thing. I screwed up the flaps on my first on ans had to redo them. I cut the hinge points flush with the surface then took a small drill bit and drilled down through the center of the piece that was left. The heat from drilling softened the epoxy and then stub of the hinge pulled right out. Then it was just a matter of cleaning out the holes and putting new Robart hinge points in. Make sure the knuckle of the hinges all line up with each other perfectly and are all the same distance from the surface.
KaP2011