i've never heard of anyone putting fiberglass resin on a swimbait, or any bait at all...
are you trying to put this on for the clear coat?
if what you are after is a thick, strong, clearcoat, then you should use Devcon 2-Ton epoxy. pick it up at your hardware store. comes in a two part syringe.
what most people do is mix this stuff reallllllly well on a post-it or the bottom of a soda can, and then brush it evenly on the bait.
then they rig their bait up on a lure turner, which slowly rotates the lure so that the epoxy will not sag or run.
hope that helped a little.