RE: WACO YMF
No I'm scratching this model which is why I'm so anxious to get the new cowl.. I have nothing to use until I get the new cowl or I order the wrong one from the other Fiberglass supplier. "Wrong" because the model I'm copying at out local airport is a Waco Classic and the blisters are evenly spaced.
I've taken Angels idea and cut the radius out of about a 3" piece of 2X4 and I'll glue some 80 grit inside it. Will switch to a finer grit as I get close to the shape.