Thank you all for your suggestions, and for taking the time out to entertain my question! The event is over, and I hate my painting. Ha! The good news is, this very amazing and beautiful musician has agreed to sit for me for a REAL portrait soon.
Well, I brought several lights with me, but ended up relying on the street light nearby for illumination. I had every single thing against me: crowds standing between me and the stage, people tripping over my easel, everyone talking to me, no lighting whatsoever on the band ... even with all those obstacles, the painting was a hit for the people watching and I sold two other plein air paintings as a result.
If I get the guts to expose myself in such an unflattering manner, perhaps I will post a picture of this disasterous one hour portrait.
Now it's time to get back to business ...
PS: Claudemir, I absolutely loved your honest statement about photos! I agree!