if you could handle a whole day, i think you'll be able to watch all shows and do all rides. be sure to come about 20min early before the show to get good seat, but now the summer season is over, i think 10-15min early should be ok too.
during the no-show break (around 2-5pm) you can have lunch, visit the dolphin cove or shamu underwater viewing.
we live 2hr from orlando and visit sw about once a month, usually we arrive around 3-4pm then visit shamu underwater viewing and watch oddysea, blue horizon and shamu rocks.
if we want to feed the dolphin, we around 2, i think that's the last feeding time.
have fun at seaworld!