Biots smooth and fuzzy

wrapping biots I seem to have trouble consistently getting a smooth ( or
fuzzy, whichever is the goal) body, even though I've seen the info about the
notch placement to control this. Is there some other indicator ( I'm
thinking maybe the natural curve of the barb) that I can use, sometimes,
especially with turkey biots, I can't really see that 'notch" and kinda
guess.

Smooth biot help appreciated, thanks in advance