Aha! Finally figured out what to do with this toggle. It's a nice toggle, two-sided, but it's terrible for necklaces...very hard to close. And for a single-strand bracelet, likewise it doesn't work. It holds but just doesn't look right.
I'm not 100% finished with this piece, if you look closely you'll see there's too much crowding on the diamond-shaped part of the toggle. I'm going to attach the strands to a jump ring and then use another jump ring to attach to the clasp.