Got some tips from the factory:
"We actually “top” each pipe by hand which we do with some sandpaper on a rotating disc. This is done before we spray varnish the pipes. Since the pipe is put upside down on a peg to spray varnish, I don’t think there is a lot of varnish that actually gets on the top of the pipe. If you do decide to use a little spray varnish, you may want to consider blocking the tobacco hole in some fashion so the varnish doesn’t get into the tobacco chamber."
"...we buy our lacquer in large drums and it is an industrial type lacquer. I’m not sure what type of lacquer that is available on a consumer level that would be similar. You may want to look for something that is water based."