How about some of your techniques to patch holes in Fiberglass cowlings? I had to remount my cowl after changing engines and now I have 5 holes which are about 3/8" dia. in the cowl where it was previously mounted..I was thinking of laying a thin patch of glass cloth on the back side then filling the holes with body putty or light wood filler then sanding and repainting..or maybe filling sanding smooth and monokote over holes..quicker but probally wouldn't look as good as painted..