I am planking a Catspaw dingy in lapstrake. greg Rossel's book and Leathermanmake it a point that the overlaps must be flat. The importance of this as I understand is the if the overlaps are concave the boat will leak. However in "Building the Hershoff Dingy" they emphasize that the overlaps should be convex to ensure the boat will not leak. Does anyone have an opinion on this and what is the best way to cut a convex overlap? i have been using a 1/2" gouge and a rounded sander. i get the convexity but sometimes it is not exaxtly straight.