Anything over 5'x6', to me is a waste, plus, if its deeper than 5', one man can't sit in the middle and see, because theres too much room between you and the window. Second of all, unless you plan to bowhunt the stand, only make the windows 8" tall. I've seen some, people could jump out of. Third, know where the stand is going before you build it, because looking uphill, or down hill, will affect window height.