Pretty much all the shows ae just show up and find a seat, at some shows they won't let you in once the show starts. You need to get a seat early at the Sea Lion show, the preshow for it is about as good as the show
The only one that I know that can fill up quickly is Belive...so depending on how busy it is on the day you are going is how early you need to get in line. We were there early last June with no issues, heck we walked into that show right as it was starting.