I'm a little sceptical of wind chill, it's kind of like an exaggerated temp.
Esp. in the mountains in winter, you're always wearing windproof everything, so wind chill is really a non-issue.
Used to wear rubber painter's gloves (like surgical gloves but thicker and much cheaper) under polartec liners, my hands were toasty all day but shriveled like prunes. Some people (esp Mountain Rescue) wear VBL (vapor barrier liner) underwear but I never went that far. Knew some of the Mountain Rescue guys who absolutely swear by it. Oh yeah, plastic grocery bags on the feet, followed by socks and books. Same principle, cheapskate's VBL but extremely effective.