ck1, as usual we are on the same page. I've been reading the same book as well.
Diane, Yes you would be very surprised at the number of deaths due to lack of water. You may just want to take Bright Angel down and just do refills on the way. South Kaibab is a great view, the exposure and lack of water could be stressfull though. If you can prepare for the trip by 'acclimating' yourself to hiking in the heat before then, you should be OK. Prehydrating and a good diet the night before will go a long way as well. If you get down in 4 hours, that's a quart an hour. I don't remember how much I drank on the way down, it was far less than 100 ounces and we had clouds with temperatures in the low 70's.
'Alright now look over here and smile! and pretend like you're having a good time!'