Building some classix for my bedroom.It definitely improved my center's shine after I waxed it, that was on crappy lacquer spray can without a clear coat though. And I think I waxed it too early, it's supposed to cure for a month, I did it right away. I think it might have been part of the cause of the seams showing through, as it sealed the lacquer and forced it to cure into the MDF instead of the air. I don't know though I'm just guessing.
What speakers are you building? Or you're just touching up your JBL's?