Sorry, somehow I missed the reply and would have responded much sooner than this.

Not completely, did tend to soften the finish a little. The cracks did not show up white even after attempting to repair them. The surface is a maple, slightly warm in color. (probably tinted)
I finally sanded down to the wood surface, which lightened the finish somewhat in a few places, it seems that the cracks appearance will not totally go away, I can only assume that the surface of the maple veneer was damaged to some degree. I was concerned to cut into the veneer and opted to not sand any deeper. I was using 400 and up grit to do my best to protect the drum appearance. The biggest crack which went with the grain of the wood actually damaged the veneer enough that it will remain a scar on the drum. I assume that whatever damaged the drum was something perhaps the shape of the round head of a ball hammer, but small perhaps a half inch in diameter. I could barely feel the indent on the inside of the drum's surface, so whatever caused the damage hit pretty hard. I was told the finish was nitrocellulose but it may have been catalyzed to harden it and thus my attempts to work without sanding were less than successful. I originally attempted to just widen the cracks and apply lacquer + thinner to hopefully cause the melding of the cracks with the additional lacquer, but that had no effect. A website that helps with instrument repairs suggested the expanding the cracks and applying a lacquer fill to dissolve the edges into the newly applied lacquer. 90%, with the exception of the one crack along the grain, are almost invisible except when viewed from just the right angle. I have applied approximately 8-10 thin coats of lacquer, have sanded to 2500 grit. Need to get it to a gloss finish now.

This is the first time I have ever so patiently worked on something that needed a good repair that hopefully would be near invisible, right now it is close, but no cigar. I have learned a lot, mostly that there is so much to know that I do not know. I am sure that I should have attacked this from a different direction, but at that time I did not know any better.

Ken