Ever heard of a thing called a cable pulling sock? It works on the same principle as the Chinese finger traps you might have fooled around with when you were a kid. Shove your fingers in and try to pull them out. The harder you try to pull your fingers out the tighter they stick. That’s what a cable pulling sock does. It only tightens relative to the pulling force applied. I used them when I used to work with cranes.
I don’t know this for sure, I’ve never tried it, but I suspect you could adapt that to hang a weight. Those are specially made to distribute the pulling stresses widely so it doesn’t slip off the end of the cable. Widely and evenly distributed stresses has to be an ingredient of such an all day beast if I had to design it. Look that up sometime and watch a video of how they work, you’ll get the idea. I think just making a Chinese finger trap might be better even than that. There’s videos on the net that show you how to wind them. The problem is material. I’ve tried but haven’t found a material suitable yet. It has to be somewhat stiff, and rigid, and strong, yet still workable. Boot leather is the next thing I’m going to try eventually at some point. I think it could be done if somebody hit into the right material.
Smooth, evenly distributed pulling, hard tightening, but only as hard as needed and not another joule more. That’s the idea as I see it.