If you get two and can't find a date, you can always sell it at the show. There's always someone at the last minute looking for a ticket.
Best advice, if you love the man's music, get tickets now!
Anyway, my best friend and I shall be there. He was a sweetheart and bought two tickets. I told him that I'd pay him back once I get payed. I'm just totally thrilled that I'm finally going to get to see Nick Cave in person.
I wonder though, is it just going to be him and the bad seeds? Personally, I'd be fine with just having 2 or 3 hours of just him and the band!