I own a tourer with a butterfly bar mounted with the near flats rising. This puts the far flats rising towards the outside of my wrists. I have, however, seen butterfly bars mounted so that compared to the stem the near flats drop. This would put my far flats falling towards the outside of my wrists (a position I suspect I may like better. But I'm having difficulty finding comparative evaluations of mounting butterfly bars in these manners.
Mounted dropping: http://sheldonbrown.com/deakins/images/flatandtrek.jpg