Well number one, going over 20' high for a bowstand is asking for trouble, especially if the deer are 15 yards or less when you shoot. High shot angles make for a much reduced kill zone window.
There are other things that you can do involving treestand placement that should reduce the chances that will be seen.
1. When at all possible, try to pick a tree that has multiple trunks, or a branch or two where you place your stand.
2. Terrain plays a big role. ALWAYS try to set up so that you are above the deer's most likely path of approach. This is also where being above 20' can be a deteriment, as that will only increase the height of the shot angle.
3. If the deer trail you are setting up on has a bend or curve in it...however slight...try to set up in a tree that's on the INSIDE of that bend, as the deer's eyes will not naturally be looking straight at you but away from you as they travel the curve.
4. Try also to select a tree who's backdrop is not open sky, or a field, or some other view that will make you stand out. When you find a tree, walk around it and view it from different angles to make sure that the "skylight" factor is low or non-existant as possible for the likely path of approach.
5. Time of day when you will most likely be hunting that stand is a REAL big factor. NEVER, EVER sit a stand where you are facing the sun for that time of day. You may as well have a flashing neon sigh that says, "YOO HOO DEER...HERE I AM!" Always try to plan it so that you will be on the shady side of the tree for the part of day that you will be hunting it.
Very few, if any, treestand sites will offer all of these things, especially for an archer. Most of us select several stand sites on the property we hunt for times of day, wind conditions, etc. For me, it's all part of the challenge and fun of the hunt. Sometimes you win, most of the time the deer win!
Offer No Apologies.....
NRA Endowment Life Member