Just adding to what others have said.
You are guaranteed a seat but the closer to show time the worse the seat is
I go every year using standby so I am seated fairly early, in the back rows and have gotten to see how the theater is filled.
Dinning packages take almost the entire theater, with VIP and choir directors towards the front right.
Dinning package people that arrive 10 minutes before the show have a seat but it is usually the ones behind trees (there are a lot of trees in this theater) or they have to separate, and fill in whatever is left. So don't wait too long.