While making my first mould I ran into the problem that the gelcoat was repelled so much from the Easy-Lease-covered surface that it was very hard to get the whole surface covered, once painted on the gelcoat would slowly develop bigger and bigger holes and basically pool in the lowest spot, even though that it wasn't thin at all. It took about three applications to get acceptable coverage that was still very thin in some places. I knew that it wasn't tooling gelcoat, I couldn't afford to order any right now, so I used an epoxy gelcoat that I had. Basically I guess that it just wasn't a suitable product for this application, but can I be sure that once I get a proper tooling gelcoat for future projects it will not sport the same behaviour?

Kind regards
Martin

No it likely will still occur, its a common issue with high slip chemical release agents like Easylease. You sort of have to keep brushing it until the gelcoat becomes thixotropic enough to not open up again. 

Some gelcoats are worse than others. It shouldn't be such a big issue that it is impossible to form a closed surface, it should just be something you have to pay attention to. So if your gelcoat is absolutely not working, then it probably isn't suitable. Tooling gelcoats tend to be better at resisting fisheyes as they are quite thixotropic by nature, while for example a spray gelcoat would be almost impossible to brush on well.