Newbie Whoopie sling question

so I've been reading about whoopie slings and watching videos and the one thing I'm unsure about is how do you tighten up the sling? Is it just a matter of pulling on the tail/back splice until the desired tension is achieved? If so, doe the structure of the whoopie sling then prevent the tension from loosening?
I don't even have my wbbb yet and I'm already starting to think mods!! Is that normal...wait I take that back, I really don't think there is such a thing as normal with hangers!
Thanks,

sd

You can see it here at 6:30 ........
Hoping that helps a wee bit.
Shug

That pretty much answers my question. Thanks much Shug. Don't know how I missed that one as I've seen most of your videos. Gotta send you a couple Coffee Crisp for helping out.