You might try shooting a coat of clear Createx, like transparent base, over the whole bait, heat setting it, and then coating it with your epoxy, using nitril gloves to keep you finger oils off of the bait.
Someone here suggested applying the epoxy with a gloved finger, instead of a brush. That would force the epoxy onto the bait with good contact to the surface, may trap less air than brushing might.
Last, if you're using Devcon 30 minute, and get bare spots, after it cures out, put some epoxy on just the bare spots, let it cure, sand any irregularities smooth, wipe with alcohol, and then recoat with another batch of epoxy.
I seldom use epoxy any more for just these issues.