soft shackle.. i think of opies bury and eye.
nacrabiner.. i think of a diamond knot, that locks with a standing larks head.
i prefer the nacrabiner in this instance. never had real luck milking a soft shackle to make it worthwhile. i use a nacrabiner on my wbbb ridgeline, so i can detach it and use it as a chair more comfortably.
(no ridgeline on a wbbb makes it a dreamy hmmk to chill out in)