I had the same issue in my car , come to find out the sender was not aligned correctly . I have to loosen the plastic locking ring and move it a small amount. The float was stuck on the inside of the tank. I would take another look at it just to be sure.
Look into Xentec , they are cheap. Ive used them in every vehicle ive owned. I cant see to drive at night due to glare , they help out alot. Just remember to reverse the polarity as it looks like you will be putting them into a 2g. Oh and they are cheap. Never had an issue with them.
Have you tried using air to blow off the bondo when your done laying. also go over it with some seal skin , or a top coat of polyester filler. the bubbles will go away. 2k High build primer after that. Block her down and shoot!