There are two mount lines, core center, and suggested. The suggested mount is like 5 cm back from center (where mine are mounted at). I rode a pair last year at core center, and they had a constant going over the handle bars feel in pow. If you do nothing but backcountry booters, center might be fine, but if you ever ski the pow instead of jumping over it, you should mount them boot center. I mounted mine this year at boot center, and I have been told the feeling is much better in pow.
Hope that helps, since unlike the two before, I have actually ridden them.