I have only just found this forum, but felt compelled to have my say! I am based in Calgary, Alberta, Canada. Humidity is normally quite low due to the altitude.
I used to have exactly the same issues as BrunZ320 until I tried 2 things that worked.
I tried more than 5 different epoxies that all blistered and bubbled until I found Crystal Clear Epoxy from www.eastcoastresin.com, which is the easiest I have ever tried. It doesn't seem to matter if it has been handled without gloves or if there any contaminants on the lure surface. However, I find that if, after painting is completed and left to dry overnight, I airbrush a coat or two of Varathane Triple Thick Clear Finish diluted with 20% water (It is an acrylic product), it provides the perfect key for Crystal Clear epoxy. I let the final coating dry for 24 hours before painting on the epoxy. Beautiful high gloss perfect results every time using using a cheap barbecue spit with 2.5 rotations a minute.
I got the idea of using this mid-coat from Engineered Angler on YouTube, he is amazing!