Do the switches you got have any hide left on them? In the old days we used to leave a strip of hide, 3" or so long, and attach that to the tail with zip ties. Back then we tied the tails up higher, though - this meant the balled up switch would cover the part where it was attached. Not sure how well this would work now that everyone leaves them hanging lower - you'd just have to experiment with it to see how it looks best.
I'd go with the baler twine, myself. Cut about a 3 1/2' - 4' piece of hemp twine, unravel it as much as you can, then shape with adhesive and paint it. When you're ready to use it, stick a couple of zip ties through it, use those to attach it to the tail - touch it up with adhesive and paint and you're good to go. It's really easy, fast (you can have it ready to put on before you start fitting), and looks good.