I'm new to the forum, but I've dived headfirst into hanging and diy'd my whole set up so far. The one piece that's stuck in my head is the whoopie sling. It's simple, but manages to do something that could easily be overcomplicated with other methods. That being said I do see that it could be improved slightly by eliminating the weak spot that lies between the two buries. It's the only part on the sling that isn't doubled up in some way.
My idea is simply to overlap the buries. The adjustable bury would simply come out of the line some distance past the end of the bury for the eye. The two inner lines run beside each other not through one another.
I've just done this with some mason line, and it's still easy to adjust. I don't see any issue with this on small line. The thing I'm most curious about is if two pieces of amsteel will fit inside the other part and still function. There's also the possibility that this much material will weaken the line to the point that this isn't a useful method.
If this were to work in theory it may be worth trying on smaller line than usual since it will increase the breaking strength. That might eliminate some of the issues with the larger line.
I also think that if I can figure out how to bury part of the adjustable bury inside of the fixed bury(don't ask me how) it may work better and possibly eliminate the need for the locked-brummel at the eye splice. That will be a bury in a bury. We'll call it whoopie-ception or something.
I think that's all I had to say. Chime in with comments and whatnot. The one I've already made is going to stay that way. Another is on the way for some unscientific testing.
Oh, if this doesn't make sense then let me know. It's late.