hey bro we just set one up in town. tied to a plane tree on top of the hill and attached the bottom to another tree through a fiddle block at the bottom. as a brake we attached some slings with fall arrest bungys at the last ten and 5 metres. the fox was about 85m long, it worked sweet.went down ona petzl tandem pulley though i reckon any pulley would do really. think theres some pics on facebook