Al my other atempts have had pinholes. I know they can be fixed by applying gelcoat in the holes. But it takes time, and I usually dont get the same goss after sanding down the applyed gel coat. 

I agree with Mark, the epoxy tooling system is extremely viscous and you need to be very meticulous about the way you apply the gelcoat. You will find the Unimould system is somewhat more forgiving.