Hmm. CA you really got me curious now. That whip sling looks just like the form I use on my signal whips. It looks like a Balearic core with tapered plaiting on the outside. I'm going to give this a try.
Debating though if I should change the design and plait up to the split pouch, stop and start an individual plait for each split. Stop again and continue the rest of the sling/whip.
That or I can run a continuous plait down the entire sling including the pouch to the release.
I'll work on a prototype in the next coming weeks. If I like what becomes of it I'll post pictures. If I really like what I see and how it works, I'll send you a message CA for what 2 colors you like
This ain't slinging but here is a demo of my Boy using two of my custom 8ft snake-whips.
https://www.youtube.com/watch?v=yP0Wla-VonUThe sling won't be that long of course but I'd be modifying it to my micro-whips which are 5ft long. Equivalent to a 30" sling from pouch.