Saw them in 1983, at Mountain Aire, outside Angles Camp at the Calaveras County fair grounds.
I used to live right around the corner in Diamond Springs (more like 1000 corners, on that road).
Anyway, I'm a big believer in a mustard base for my butts and ribs especially - not only as glue for the rub, but I'm convinced the bark is better. I also prefer to use the cheapest store brand mustard I can find, I don't know if it's got more vinegar or what, but I swear it works best.
As with everything technique related, we've all got our preferences on how to do things, and there's no one right way - I like these sorts of discussions because I always learn some new angle.