I hate retuning the 12 string but it does sound glorious in DADGAD, so I've been using it lately for accompanying slow airs and songs in that tuning, and using the 6's for standard and other tunings. For this I generally use medium guage strings since the average string tension is much lower than standard, and the strings don't flop around too much. It somewhat satisfies my lust for a bouzouki, since I can't afford one right now, and gives a certain un-guitarlike timbre to things I play. Sounds great with the fiddle too.

Peace. Mooh.