Zen:

I'd zero it in to hit dead on at 100 yards. With a 100 yard zero you should be good to go for hunting at ranges between 20 and 200 yards. I think what you're referring to as power is actually the adjustment for the objective lens (AO) which is the dial on the lens that's farthest away from your eye. When you adjust the objective lens what you're doing is bringing the target into focus at that range. The power setting or zoom is found on the dial closest to your eye and it's used to magnify the image. In your case the magnification ranges between 4 to 12 times what it would appear to the naked eye.