you got it chuck. if you're on level ground standing next to the tree you're going to climb, and a deer walks and sits down 20 yards away from you, you'd use your 20 pin to take it. now, if you climbed 100 feet up that tree and that deer just sat there the whole time, to take that deer you would use your 20 yard pin. so, when in the tree stand, and you're wondering what pin to use if the deer walks out here or there, how far is that deer from the base of your tree - that's what pin to use. a good way is to figure out how far trees are from you at your height in the tree. if you are 20 ft up a tree, get the distance to other trees at 20 ft up. figure out which tree is 20 yards from you horizontally. if a deer walks by that tree you use your 20 pin. the only thing that is important is the horizontal distance. the vertical distance is meaningless.