i use a washburn 12 string. and this thing is built ford tough. i tune it 1/2 step down which would be EbEb AbAb etc.....i don't do it to save the neck, i just do it because i like the way guitars sound tuned this way. to me, when tuning a 12 string you have to be able to tune by ear. you can use a tuner to get it close. but each string has to be tunes the the other, otherwise it will never sound in tune. i tune the thicker string first then i tune the octave string to the thicker string. if you use a tuner they will always be a little off, since there is a range in which the tuner will say the string is in tune.