I've never seen anything like that before in my life. Do the blades actually spin or just wobble? Have you done this with willows?
They spin like any other spinnerbait. The blades will spin in the same direction opposing each other. In other words, if the gold blade is at 12:00 then the silver blade will be at 6:00.
You can use any blade style you want. I haven't tried using 2 different blades, although I can imagine what that would produce and it's a great idea.
I would recommend going 1 size smaller than your biggest blade you would put on a bait, that way its not over torqueing it on the retrieve.
A single blade will have a "chopping" sound to it, a double blade will cancel each other out and give it more of a "whir" sound to it.
Get an old spinnerbait and cut the "P" bend off, install the blades and give it a whirl! I've been using it for 3 or 4 years now and will not leave home without it.
Here's a vid of a double cowgirl musky lure, The blades on this lure share the same characteristics of the one I posted. If you study the clevis' in the vid, you'll see that the blades will be opposed to each other,double cowgirl lure - Bing video