So science wise….

3000 Grit for Dry Lubes

100,000 Grit for oils

However, may have raced with 100k for graphite with great results as feedback will show. Science says graphite is carbon, diamond is carbon. If you polish higher than 3k and you were to take a scope and look at things, the graphite will knock the shine off your 100k axles down to about 3k on the surface of things.