We've been twice now in August. We found the trick is to be at the turnstiles half an hour before the official opening time. We find they usually open about 15 min early.
Lines aren't too bad until about 11 am. By 1 pm lines for the headliners are pretty long. DD, DS and DN waited 90 minutes to ride Hulk after 1 pm. At 9 am they were on in less than 10 minutes.