I use a bungee cord strung from the gas line in the basement for my low LOT. Then when I want to increase tension, I roll back in my desk chair. The bungee is one of those 30” long things that keeps my hope up. The pipe has only wiggled once. Besides, I make sure the hook is equi-distant between the supports. But I could see where my warm-up could get exciting.
Flacid stretch is 8 1/2” which is a meaningless number but I like nice, round, long, numbers.