I am not clear as to the final coat your going to sand. I assume you are doing final sanding on several coats. for base coat use 500 to 800 grit wet paper, using plenty of water and light pressure. for the first clear coat use 1000 grit wet. for final clear coat use 2500 - 3000 grit wet paper with plenty of water and light pressure. then finish with white clear coat polishing compound. I recommend hand application and frequent inspection of the results.
