If you use a structural ridge line to get the same sag angle each time (thus partially solving the problem of not being able to reach high enough on the trees), the limiting factor becomes upper body strength. The multiplying force on the main suspension ropes gets so high that it's very difficult to tighten them enough for distances over 25 ft. Also, after you've struggled mightily to tighten your suspension enough, you'd better have a marlin spike in it somewhere, or you'll never get it down without using a knife.