It'll be fine, just give Windows about 30~gbs
Once you're in, delete the paging file and disable hibernation. That'll free up some space.
EDIT: Well, I don't know your intentions and I don't know how much you have in use right now, but you can also split 50 - 50. Your choice, but it WILL work. My 11 Air performs as good as a PC (or maybe better)