For years I tuned my 12 string a step down and used the capo although it's actually more fun to play without the device. A few years back I got to thinking about it and decided to just play songs in a different key. For example when the other guys are playing in "D" I play the 12 string in the key of "E" (it's actually the "E" fingering but really the key of "D" if you get what I mean). Another advantage of this is that it gives a greater range of notes when playing with other folks - especially other guitar players.