The height of my tree stand depends on the cover I have available. If I can get away with 12-15 ft I will. 10's even better! I don't go any more than 20 ft unless it's a forked tree and I know I will feel safe with another tree close. Yes I wear a saftey harness but something to put my hand on when I fall makes me feel even better. LOL
I feel the same way I am scared of heights and feel a little better with another tree close to me (Ihave good success from the tree stand that is why I keep climbing if anybody was going to ask) I can feel my comfort level when climbing and that is where I stop it is different for each setup . The worst part for me is taking off my foot straps and turning away from the tree after that I am ok as long as my platform is fairly level