Here is the official time for Registration:
Last Chance Qualifier Registration (TCG) 9:00am - 10:00am
I would suggest being in line starting by 7 - 7:30 just to make sure you are in it before the cap the grinder. I know in the past they have let in people after the max was reached, at least in '06 they did, but that is not a guarantee.
There's no cap now, and they won't let you register until 7am...that is if beach is right.