I got the fiberglass laid over the weekend:
As it's my first attempt it's nowhere near perfect but it should still work. I ended up using only two layers because I bought heavier mat. It just has to be able to hold the fan anyway. It was hard getting bubbles out because after laying about 1/2 the first layer my roller fouled up with resin and was pushing the mat around. If I did it all again I'd cut larger pieces of mat and do whole sections at once. Tonight I'll start trimming and sanding. If it turns out crap I'll just try again.