I am building a DIY backyard zip line - total length is 175 ft, starting anchor is a steel pole (6 inch diameter) - 21 ft long, I plan to bury in lots of cement about 4 ft deep - cable will be attached near the top, no guy wires planned, I will "board" the seat on a tree fort near the top of the cable, the lower anchor will be a solid tree - I will anchor it near ground level by various websites and my own research - every 100 ft you need 6 ft elevation change, and also 2 ft slag for every 100 ft of line, my starting height is about 9 ft platform/tree fort, but the cable will be around 15 ft high Dont worry, I wont be hitting the tree to stop - I have grass in front of the anchor tree, and can attach a bungey system to slow down and stop Questions::::: how deep to bury the pole?? how big diameter of pole?? what about 4 inch diameter?? do I need guy-wires to support anchor pole? how big of cable size?? I am about 200 lbs, children are lighter. Can it support me??