580ex and AB800

Would this set-up be able to capture a group of say 8 people? I'm just thinking outloud and haven't tested it out yet since I'm not at home. I'm thinking of having the AB800 to use as a main light with perhaps a reflector for fill. The 580ex will be shot against the background. Can I fire the 580ex bare? I suppose I should use a softbox?

In terms of power, would the 580ex2 be able to handle with the AB800 at a relative usable range?

Thanks.

What sort of background are you talking about here? Are you talking about a white backdrop or similar that you want to blow out with the sole 580?

Measurements of flash power here. Tell us more about what you're trying to do, and where.