I build selfwood bows but I imagine the process is the same.
I start with 80-100 grit to get all tool marks out--being carefull to not be too aggressive in sensitive areas.
Remember, your the artist, it's up to you what comes off, what gets rounded ect.
I go from 100 thru 400 in what ever increments I have on hand. Im sure you can go finer, I never have. I think some finishes suggest stopping at 220. Im not sure why.
I found that if you spill beer on the wood and let it dry it will lift up the grain of the wood and expose sanding inperfections that were hidden.Sand again 150-->400grt.
Good luck,
Scott.
PS. It doesn't have to be beer. Im sure any adult beverage will work.