I generally hunt from 20-26ft. up which is just right for my area. I find that sometimes if you get too high that shot placement becomes extremely critical the higher you go leaving very little margin for error and secondly sometimes if i you get too high you can be even more skylined then if your only 15 ft. up a tree. My rule is you want to be as high as the most amount of cover whether it be 12ft. or 30.