Used Bondo filler to smooth contour of fiberglass over foam. Sanded, and added more fiberglass, and sanded again. Its far from perfectly smooth, but ok for now. Cut the spinner hole to final size and reassembled. Looks much better than it did before. I'm going to trim the back side of the cowl still, but for my 1st fiberglass project, I'm satisfied. I'm sure there will still be some prep work before painting or final finishing.