fj. here is why. you then have a chance to queue up early for kong. and you can ride it with minimal wait. then you can decide if you want to experience it again, and you have the rest of that day and the entire next day to watch for wait times to see when a good time to ride it will be. if you do gringotts first, you most likely wont do kong until your second day because of the wait, and you may decide that you want to ride it again, but the waits are too much. riding it the first day in the first hour, gives you the most time to ride it again if you want to.