My brother has a nice Gibson ES333 that has some tuning problems so he decided to install a new Groover tuners. As this ones have only one screw to fix them, he found that after the installation he has six exposed holes. He go to the store and bought some mahogany coloured filler but when he pshed the filler into the holes he found that this disolve the (nitro, I think)finish, so the result was worse than the solution. My plan is to mix some dyes (amber, red and hazelnut) and try it in a mahoghany scrap until I found the right color. The question is: what shall I put on top of this, nitro, shellac?. Any advice?