Caring for Giants was very cool if you are interested in elephants as well, in case you can't get the rhinos. As mentioned Rhino tour is only once a day, while Giants is 5-6 times a day I believe, so more spots available. We booked it only a few days in advance, and were able to change from morning to afternoon the day of when we arrived at the check-in. Would love to do Rhinos next time, but know it's a slim chance unless we are able to book at 180 days.