A superior “mid-air binder” has been presented now in a couple
of threads, starting with my presentation here:
http://igkt.net/sm/index.php?topic=1449.msg10281;topicseen#msg10281
… and repeated & reiterated here:
http://igkt.net/sm/index.php?topic=2996.0
I just fiddled this in 2mm? PP kernmantle, which nicely holds
a 25# weight; and in 1/4" PP 3-strand rope, which holds but
which I can’t further hoist/tension a 37# weight (one end of
the structure is girth-hitched to 'biner clipping weight, the
other runs around a 'biner at the top; I’m hauling downwards
trying to increase tension, but in vain). YMMV.