If you are going in as standby, 60 minutes as Robo suggested is best. Only the seating area on the right-side of the amphitheater is for standby guests. Once that area fills, sometimes as early as 30 minutes before the show, the remaining standby guests are held in the entrance pathway. They are allowed into the amphitheater 5 minutes before showtime to fill in the Fp+ area - all the sections to the left of the Dining Area.