To add to what Hida Man said...
I just got off the phone with a gal at that borders. Couple important bits of info.
1.)He will sign a maximum of 2 books per person.
2.)Wristbands can be acquired at any time, and you can, potentially, get more than 1. In other words, I can get 1 for me, and a couple for friends. They only determine place in line.
3.)She didn't have any estimates on size beyond "I hope it's not overcrowded". She did state there are only about 30 actual seats for this event. So, people who want to sit in a chair should be early.
4.)They have over a hundred copies of Changes in stock. Or rather, they ordered 100-150 extra. Something like that.
So. Gives us a pretty good tactical picture of the situation, as it were.
I plan to coordinate with my two friends this weekend. I also foresee likely being at the "mid-afternoon lunch" thing, whether I eat or not. Possibly also going afterwards for food.
Though laura118b has a good point about being further back and actually getting to say more than 2 words to him.