I would say 10 just to be safe. It'd suck to get up at noon thinking you're going to be trying for tickets to see that they have been sold out for 2 hours. I've had good luck with tix so far this year with 3 different U2 shows so lets hope the streak of luck continues. Everyone I know has been enlisted to try and swing something but we shall see. At least you have the comfort knowing that the guys will back in the Northeast on August 6th @ The Tweeter Center in Mansfield, MA and hopefully @ The Meadows in Hartford, CT during that same trip and the lawn for those shows will be nothing to get.