To keep things consistent from side to side, it's smart to make a template for the shape you want. Bobco already had this template on hand, since rounding door corners on a '56 F-100 is common practice there. The two square corners are at the top of the vertical edge between the door and cowl, and the top front edge of the window frame. Both areas were ground clean of all prior bodywork, and then the top template was lined up and marked first.