Thanks for the love, brother! Yep, I got it to work. These Saginaw Columns are wonderful beasts. I had an extra horn pigtail laying around so I cut the portion marked in red, leaving the brass contact and some yellow wire left in the spring portion for rigidity. The horn works beautifully, only quirk (which I can deal with) is the horn button doesn't sit "level". Otherwise, it works perfectly fine; you can hit the horn button from anywhere and honk it! My neighbors hate me because I didn't disconnect the battery and kept accidentally honking it (with Cadillac 4-note horns, it's loud).
I wish I could find a set of 4 note horns that work. I've been duped on 3 sets so far and I'm not buying a fourth