Ok I think I figured this whoopie sling thing out...the way you make these things is to first go back to college and get a PHD in mathmatics, physics, and engineering then buy a spool of amsteel, spend months trying to make your own whoopie slings, finally give up and just buy a set of them made by someone who understands the first 10 pages of this thread.
But seriously, great OP, now I just need to figure out how long of slings I want/need. Thanks SlowBro!
P.S. What lengths do people tend to go with, assuming 6-8 foot huggers?