The rain stopped so I did a little testing. Note: I'm 5' 11" and weigh 158#. I strung my Hennessy hammock between two trees 12' 6" apart with a Dynafor electronic load cell, set to record peak load, in the foot end suspension line. I tensioned the lines the way I usually do which is snug but not pulled tight. That measured 5" of sag. I then climbed in a bit less gently than a normally do and bounced around a little. The peak load was 180#. Then I pulled the suspension lines as tight as I could without resorting to a truckers hitch and climbed in again. Peak load 212#. I switched to trees 17' apart and and repeated the test. Peak load with a little sag 228# and pulled up tight 254#. Granted I'm not a worst-case test load but it looks like any device with a working load rating over 600# should be good for anyone. I think I would stay away from the "key ring" biners and dog clips.