"Swipting" means spread something into the holes to fill them. There are all kinds of ideas on this. Some people use resin with micro balloons or glass power. But the resin is harder than the fiber glass part so sanding it smooth is difficult. I used Evercoat Glazing compond. It is very fine and fills easily. It tries very quickly. Or I should say, cures. It doesn't swipe real well. I probably should try thinning it to make is swipe better. so I had a lot of sanding to get off all the excess.
In middle photo you can see all the excess. Right photo shows the holes filled and the excess has been sanded off.