Aperture Priority: As, at night, you will be shooting on a tripod because there is limited light, there is little point controlling shutter speed and because we are shooting things at a distance, there is little problem with shooting at the widest aperture that the lens can manag
I've been lucky enough to do a fair few gigs in the past, primarily in small venues like 12Bar or the Windmill in Brixton, but also at some bigger venues like main stage at the Garage in Islington.