Amsteel Blue in 7/64" is rated at 1600 pounds. Subtract ~10% for the splicing. Youngmoose is right, strong enough for most humans. And even a young moose
I got my whoopieslings a week or two ago, and I gave them a first try today. I ordered the 8' and 8' because the whoopies will always go to their minimum length and the tree huggers can always be looped around twice or three times to take up the slack.
The only downside is a bit of extra weight, but I can deal with that.
I have the 8 footers and like the length. I used the extra length to tie each end to the other. This made a ridge line for my tarp. It was real windy & real cold out and I used a second tarp to help block the wind. I didn't have a lot of extra rope so the whoopie ends were put to use.