Depends on how late in the afternoon you are getting there. It also depends on the show schedule for the day you are there. For example one time when we were there this year 3 shows were scheduled in the 5 o'clock hour so it would be impossible to see 2 of them. Blue Horizons and Shamu show were scheduled in the 6 0'clock hour so almost impoossible to be at both shows because the stadiums are across the park from each other.
Sea World is a park where you can't commando through it. You want to take time to watch and feed the animals, to let the kids play in the playground, in the fountains, etc. , and to just enjoy yourselves.
My suggestion go for the afternoon and if you don't get to do all you want to get the return pass and go back for a second day.
Don't miss things : Blue Horizon, Believe, Clyde and Semore, Wild Arctic, feeding the dolphins, checking out the manatees, flamingos, et. etc. And we can't forget the hospitality house for your free sample of beer. <g>