are you doing partial suspension, or full? if it's the former, you can get away with using more unconventional ligatures like exercise bands or belts. though partial is notoriously a difficult method to pull off. but if you're doing the latter, a proper good rope is required to be safe. something like double braided dockline either polyester or polypropylene; and 12mm is ideal. mine has a breaking strength of something like 1800lbs, so something like that would be way more than enough for you.
I read here in the forum about rings that can be worn to avoid compressing the trachea too much, do they work?
the only rings I'm familiar with are the ones used by the british for executions back in the 1800s, but this was for long drop hanging and I don't believe it has any effect on trachea pressure. some people when doing partial will put socks filled with rice or cornhole bags over the arteries, so when the pressure closes around the neck the trachea remains open. not sure how feasible this is for full, though.
PS. Yesterday I tried to squeeze the sides of my neck where I feel the pulse with my fingers, but nothing happened. Maybe because my neck is too wide? Is there a risk that he won't lose consciousness until he dies?
typically, most people won't be able to properly occlude their arteries with their fingers, despite how little pressure is required. everyone's anatomy is different, but i don't see people doing it successfully very often. you could try doing a test run with that rope, making a noose but not tying the other end to something, so when you pass out you'll just wake up as the pressure will loosen when you lose consciousness. make sure you're seated when you do this, obviously.
