Well if your friend is not trying to take 50+ yard shots, the effects of wind should not be an issue. Plus, on a windy day where arrows might be effected by a gust would probably be a day not to be in the stand.
I've shot on windy days, with blazers with a mechanical and buddy with a fixed with blazers. Shooting out to 50 yards in about 15-20mph wind had about a 2 inch effect when the wind was blowing the hardest.
Your vanes will have more of effect than your broadheads in high wind conditions. Yes, less surface area exposed = less drag.