Early evening event with sb-400?
I have been asked to shoot an event at a rooftop bar in a few weeks. The event is from 4p-8p, central time. I'll have a couple 2.8 zooms and a couple primes with me. I am usually shooting landscapes and street photography, so I rarely use any light beyond whats available. I have an SB-400, but I'm wondering if should rent or buy an SB-600 (or better)? Or, do you all think I'll be ok with available light + my sb-400?
The bar is an indoor/outdoor venue. It's not too dark, and the event is during hours that are fairly well lit. Here's a link to the venue, if this helps at all.
and a google image search of the bar: