I know when extending the edge of a fiberglass part, the thickness of the part gives you enough meat to make a scarf joint and create a good bond with the new fiberglass. Is there any difference when needing to extend the edge of a metal skin? For example, I'm kicking around the idea of extending the side skins of my tip up canopy to overlap the fuselage skin maybe 1/4". The thickness of a skin doesn't allow for much of a true scarf joint. Do you just have to roughen up a larger area of the skin and make a wider transition zone with multiple layers of glass (vs a small scarf joint that essentially cuts through the thickness of material and ultimately creates a flat transition with the new fiberglass layers)? How many layers is typical for something like this?