F10 at a festival-questions

Hello, I will be taking my F10 to an outdoor Celtic music festival this weekend. Most of the perfomances will be under large tents with variable lighting. My question is, should I keep the F10 in Natural mode or Protrait mode to capture good complexions on people's faces or should I try the manual mode? Or stick with Auto? I'm new to this camera but not to digital photography.

Your advice, please.

Thanks.