Ron, Pm sent.
Depending on the tree and cover available, you will determine how high you need to be. I've used just the top section with good success inside a pine tree. I think it was about 5 or 6 feet off the ground. Remember, you can always build cover around your platform also. I know you are skilled enough to figure something out.
Sometimes if placed on a hill, you want to be high enough that the deer will not be at eye level if coming from above you, but the down hill shots can look really long.