@Jazz
Thanks for the cling film plan, it works great and is a lot less effort than the release agent. Yesterday I was mating the surfaces where my x sides bolts to my frame and I already laid down the epoxy when I realised I don't have enough cling wrap left and had to make a plan in a hurry so I ripped a page out of a magazine that was lying there. That glossy paper worked remarkably well. The paper obviously stuck to the epoxy side but I removed it with a wet cloth afterwards. Funny thing is the ink remains so you end up with an inverse print on the epoxy surface of what was on the paper.