Now don't tell anyone this but I used AutoISO which I suspect might get me a slap from the experts .
I do concert photography and I kind of laugh to myself at some of the habits and practices I see employed by others...
Like you, I also use Auto ISO 95% of the time (and everything else manual) because I figure the camera is smarter when lights are drastically changing 50X a second. But I'll watch another photographer spend 1-2 of the 3 songs we have to shoot chimping his or her ISO settings, and I just don't understand it. It's such a small window of opportunity to have it all pass by looking at the back of your camera.
Whatever gets you the shot. The camera is a tool and if Auto ISO works, I don't see a problem with using it. But I know some thing anything "auto" is bad.
So I am not alone
The great thing about this small festival that I took these at was that we could actually click away through the whole show so I did try a few odd shots. In fact by the time the fifth band came on I was actually tiring of it all . . . they weren't exactly inspirational and it was late on a Sunday night with a two hour drive home ahead of me.
AutoISO thing to me seems to work very well in such a dynamic environment. You don't want to be set at 3200 when the stage or subject gets flooded with bright light and unless you know the show it's hard to predict when that's going to happen.