How early do you have to arrive to the Tonight Show with Jay Leno Taping if you already have tickets?

I have four tickets to see the Tonight Show with Jay Leno ON Thursday March 22. The show time is 4:30 pm and the ticket says that guests must arrive in line at 3:30 pm. I want to get there early enough to get into the show, but I don't want to be waiting hours in line if I can avoid it. Has anyone gone to the show and how early did you have to arrive to get into it?