If you're talking fabric cover, I would not expect any overlap except on the leading/trailing edges, wing tips, and the 4 corners of the fuselage. Usually, these are then covered with pinked tape (or ripped tape in the case of WWI models). Any color transitions are usually paint on paint, not covering on covering. I also don't cover the ends of the ailerons or the wing cut-out for the ailerons because of all the overlaps. I brush on thinned epoxy (preferably laminating epoxy), wait a few minutes and wipe off. After it dries, a light sand with 320 and its ready for primer/paint.