Of all your many music experiences, that one has to be top of the heap. No rehearsal? Don & Dewey probably share telepathy and the bass player had been working with them for a while. Which leaves you! Talk about a high wire act. I know you don't much care for FZ (an understatement, I expect) but he did display a softer side towards Don. Bailed him out and or got his fiddle out of hock on more than one occasion, as I recall. Mighta been self-serving if he just needed him for a show or a session, I guess.
I suspect you're already familiar with it, but just in case not, check out Don's soaring solo on, "Little House I Used to Live In" on Burnt Weeny Sandwich. It starts at 5:13 on the track at the link here if you don't have patience for the lead in (and again at 10:35). Interesting set of musicians too.
https://www.youtube.com/watch?gl=SN&hl=fr&v=1AhmgaF46F8