I don't get in a hurry tillering a bow, it is a week project of shooting and checking for the slightest anomaly with my gizmo, I am only using 220 grit sandpaper at the end of the tillering process.
I got a few 1/2 finished builds in the corner from being in a hurry and gotta say that 220grit for tillering suprises me. 80 grit here.
when I take a break from tillering because my eye tell me two different things, breaking for another cup of coffee doesn't help.