Martin Carthy tunes all his guitars by twiddling those funny things on the head stock.

What about the shubbs partial capo - save taking three guitars to a gig, gives you two alternative tunings plus the ability to play "normal" chords along with partial and open tuning leads/chords ALL at the same time - I like 'em! Also handy down at the local guitar shop - no more embarrassing "sorry I snapped a string" whilst re tuning their stock.

Take care, Pete