two times round at the absolute max.
This is not scientifically but empirically determined over 20 years playing (admittedly badly most of the time however you still need to change your strings).
I use locking heads (i.e. PRS or Sperzils) these-days so I'm more of a half a turn lad !
My instructors page and www.studiotrax.net for all things recording.
my toons Brought to you by Dr BadGAS
my toons Brought to you by Dr BadGAS