Typically, when you elevated you actual gain yardage, for instance 21 yards might equate to 20 at ground level from 20 feet up.At 12 feet, the variation would be minimal. With regard to aiming for the exit hole, if you visually draw a line of the arrow passing through the deer, think abouthow high you must aim to get the arrow to exit as you imagine from your elevation. I'm sure some a little better with words might be able to explain it a little better. Best of luck.