I'm in the process of building three topwater lures I've never built before. Problem is that they have lots of moving parts, props, joints, and rotating bodies plus through wire construction. In order to seal them I kept each part separate and coated them with CA glue and since they are tuned on a lathe and have a hold going through the centre I poured CA glue through the hole and the holes where the hook hangers go (used swivels). Then to get a smooth canvas I coated them with Etex.
Only problem I have is that the CA glue ended up plugging the hole where I left the hook hangers in. Second, I don't actually know if all of the internal surfaces are coated. Note CA glue takes longer to dry on a second coat (after the first soaks into the wood), with such a small space the internal parts take much longer to dry (it was open several minutes after I was done)! Next time I think I'll leave out the hook hangers, putting a wire through it periodically could work but it could also result in a stuck wire.
Oh I have built topwaters with props before, this time I plan to paint then seal before I put the prop in place. Putting them in place first worked last time but I was real careful then had to use a knife to free up a spot.