If it's a polyester gelcoat (a special type for epoxy) you have to fully cure it before laminating onto it. An epoxy gelcoat has to be cured to an in-between stage, where it isn't liquid anymore, but still tacky.

Pinholes -that's what the in between tow cavities are called- are very hard to avoid completely with wet layup. If you use a gelcoat, the pinholes would be under the gelcoat in the end, wich is kind of worse, because you would need to sand through the gelcoat to fill them.
Depending on your vacuum pump, you have already almost everything needed for a vacuum infusion. This process is -depending on the numbers of layers- faster than wet layup and produces 100% perfect parts every time if done right.

Hi, I've been making CF panels onto glass but I don't always get the consistent finish I would like, even after doing my best to remove any bubbles from the first layer. I use Easy-Lease chemical release agent to prepare the surface of the glass and then apply some epoxy resin. I'm using a wet layup and then apply a vacuum. I'm using this method to get really good consolidation of the layers, as I'm adding defects so the panel can be examined using ultra-sonic NDT techniques and the increased density helps the sound to travel.

I find that there's sometimes very small cavities between the tow's on the top surface and although it's not a major issue I was wondering if it would be a good idea to use the GC50 gelcoat onto the easy-lease before I apply the wet material. Is this an approach you would recommend? Could I just paint a thin layer?

Thanks