I am doing the aft turtle deck on my -4. I want to break the edges with an edge rolling tool so that they will lie down flat along the upper longerons. My question is, how far from the center of the rivet line should the fold line be? The width of the fold line is built into the tool. The edge distance is not really indicated on the drawings, or I just can't find it, but judging from the other skins it is about 3/8". If I trim the panel to 3/8" from the rivet line I get the fold line right on the edge of the rivet holes. Is this ok? I would expect that there is a standard for this, any advice appreciated.