Everyone must highline different than we do. We use 2 old cinches to wrap around a couple of trees, run a rope through the buckles and put it up as high as we can reach up in the air. Usually 6+ feet. Then hang a rope down just far enough so the horse can lower it's head to a water bucket. We've never had a problem doing it that way. That fancy dohicky looks pretty snazzy to me but I still like a quick release knot.
My dream is to have those high tie things that attach to a trailer. Have to save a few $$ first though. Those are for we lightweights who "trailer" camp Tilt-Tie Horse Trailer Ties