I like the contoured grips for myself, but when I build a bow to give a way or sell, I don't do it. It might not fit the hand that wants it.
If I was to do a custom bow for someone, then I would get the rough shape done, then have the owner (if possible) old it and mark the grip areas.
So overall, I usually build smooth. Plus, I find your not supposed to be holding the bow when shooting but allowing the bow to just rest inside your thumb and forefinger. So that is the area I concentrate on the most.