Sorry GMan, had to think about this one a little. As you know, I have not done a bait as large as you apparently are doing.
At least this will push it to the top.
I have done several soft baits, smaller of course, with Alumidust. I do not find that you need to seal the dust after you are done. Still, if you don't seal it, it will not be glossy and it will, on occasion, rub a little of the dust off if you had a thick layer to begin with. In short, if you don't want to paint, then you don't have to.
I cannot suggest any other coating, other then the Alumisol thinned with softener, to seal/gloss the bait. In fact, I was even told on another forum to coat my painted soft baits with Plastisol to keep the paint from coming off.
I can suggest that it may be possible to use less Alumisol, in the clear, then you think. I don't know the shape of your lure, but let's say the lure has a volume of 100 cc. If you get a tight enough fitting container that is only say 110 cc, then you could push your bait into the container with only 10 cc of clear material in it and still get a complete coat. You would not want to leave it in there, and you might want a cooling bath handy to toss the big bait into, but .............. I don't know if my explanation is good enough, of if your bait shape will work like this, but, well, at least I have tried.
Good luck, looking to see the lure pictures soon.
PS, you might want to start a new thread asking just that question......