I would say we only use max headstay in 0-4 knots of breeze and flat seas. But this is turning into a tuning discussion and it deserves it's own thread somewhere other than the One Design Class Rules, particularly since this forum is only open to owners.

A quick search indicates maybe all this tuning talk would be better off in Mast Set Up/Rig Tension. Could somebody cut and paste from this topic say starting here?