RE: Range Finder
The issue of sighting differences based on incline (whether in the mountains or in a treestand) depends largely on the speed of your arrow, the angle of the shot and the distance. The faster your arrow, the less angle is going to matter. Even so, if you are 20 feet in the air and shooting at a target at 25 yards, your range finder would say 26 yards. This little difference can mean the difference between putting the arrow in the vitals of your whitetail or shooting high if your bow is a slow one.
If you are further up, say 40 feet, your shot will read 28 yards and many folks would use their 30 pin just a little low. If your arrow travels at 200 FPS, it would be 6.5 inches high. If your arrow travels at 280, it would only be 2.9 inches high. Now your kill zone is about 8inches in diameter and you just reduce the kill zone to a 1.1 inch target with the fast moving arrow. With the slow arrow, you just shot over the top of your target.
Anyhow, it can make a difference even when the angle isn't that large.
Be well.