I'm with Evan on this one, except that I think he meant to get at least the 120's. I skin in heavy, wet snow all the time, and I promise that having 7 mm, let alone 12 mm, of base exposed on each side will make traversing a serious pain. Ideally, you want between 4 and 5 mm of exposed base on each side of the ski, as this gives you the benefit of an exposed metal edge and full coverage.

Go with the 120mm. I have 124-90-113s and got the 120 and trimmed them down to fit. They are perfect. You could get away with the 110, but your tip and tail wont be adequately covered, which may cause you to loose traction. Dont go with the 90s, you will have wasted your money. Trimming down skins is really easy and worth the 15 minutes it takes to do it.

No!!!!! Angus is wrong on this one. Get at least 110mm width skins and trim them to fit. Alway get wall to wall skins, it makes so so so much difference when skinning on new or old tracks.

If you're hiking in powder, get 110 and cut them down. If you're hiking heavy or hardpacked snow, get 90 and save yourself the hassle. You only need the extra coverage in really light, dry snow.