We were there in January and security wasn't enforcing float size. I had one of my floats I had in storage from previous seasons and no one said a thing. It wasn't very crowded in the lazy river so it could be why it was a non-issue. I was ready to switch to a noodle if it was a problem. Others were using larger floats as well.
Good info! Our best bet will be to bring both float sizes in the event they are enforcing the rules. Hopefully it will not be too crowded in early May, the lazy river is very addictive and relaxing with a Balashi beer in your hand!