I am currently in the process of building a Pedersoli Brown Bess and want to keep the barrel in the white so that it develops that nice aged "grey" patina. What grit sandpaper should I use for the sanding? I also plan on removing by grinding or sanding the serial number and "black powder only" warnings off to make if more PC correct. I don't want to go too fine with the sanding to retard any natural aging process.