Next time use paint.

Gelcoat, while it can be used as others have pointed out, is alot more work for nothing. Particularly on the bottoms.

I used to do glass repair and the only thing you did really wrong is the acetone. Styrene is the only way to go. I never used to use mold release and I was wet sanding within hours in summer and the next day in winter.

try awlgrip...amazing stuff. Expensive tho.

for the bottoms, I'd use rustoleum from a can. Flows great, dries rock hard and sands nice. CHEAP