The event was enjoyable. I bet on the winning horse, so I really can't complain. But we decided next time we'll buy the cheap, open air seats. We paid a premium to be in the air-conditioned Grand Stand, and it was almost as hot (and more stuffy) than outside. We felt like we were in a train station, it was so packed.
If you still choose the Grand stand upper reserve, aim for sections 3-5 (close to the finish line)