Yes, there are guys using concrete sealer as a seal coat. I'm not one of them but I know a few who do. And yes, you will need to sand between seal coats if you want a smooth surface to paint on. Basically, depending on the wood your using, the first dip is going to raise the grain of the wood so when it's dry you'll need to sand it. After the second dip you might be good to go. You'll have to try it and see what it looks like. If it's still ruff you'll need to sand and dip again. One thing to watch out for is making sure the sealer is completely cured before moving on to paint. With GST it might be a few weeks??? If it's not dry it could bubble under your color coats when you heat set them. It's happened to me before on some different sealers I've used. If everything goes right and you have the paint work done, yes you will need to topcoat the lure with more GST. There is info in this thread on how many dips, time between dips, etc. Good luck!