NorCal,
Steve C and I were able to get walk-in overnight permits last year on this same weekend of Sept. I would really consider this, because you are already placing yourself in a sleep deprived situation by starting so early (my group was able to pick out the people on the switchies who had started at this time; they looked more sleepy than physically tired) Also, doing an overnight would allow you to sleep at elevation, so that you can mark acclimatization off of your list, too.
It is my personal belief that sleep deprivation and lack of acclimatization are by far worse enemies than being a bit out of shape when doing a day hike (if one was going to pick the worst of the bunch)I did my overnight last year with only one previous hike of the season -- being otherwise fit by running -- and I would denote my success to the fact that I slept late the day before the hike, napped up until entering the trail, slept at altitude, and generally approached the whole thing with a very relaxed attitude.
