I was sat right next to Harry Seaward (swear I thought he was gonna go over the rail at a couple points ). There were only about 10 reserved/VIP seats, which were dead center in the balcony. The rest were first-come, first-served.
As an aside, that was probably the largest crowd I've seen at the Regency Ballroom. Floor was packed, all upstairs seats (sans VIP) were taken, and there were people doing standing room only upstairs, too. Absolutely nuts - and absolutely awesome.