we used to use them allot when commie trolling.
we would use them for late fall coho....usually with a darkblue and silver , or something with some sparkle.
we would use longer leaders thinned out in the fall and always had a flasher just below/under the butterfly as we called them.
leader would be about 7 fathom long and keep as light as possible with small hook and no swivel in a loop knot so it hangs back a bit, and take out every second strand of hootchie tail.
THEY KILL BIG COHO ! and were not a fad/gizmo... they made us money $$$$$
you know when you have it working right if it is fluttering and vibrating , and will dart around changing directions.
have fun with them, on rod and reel they are perfect.