Originally Posted By: Chickadee
Lawnerd,
I am going to be on the trail Oct 1st with 10 of my friends as well. Are you doing a day hike or camping? I attempted a day hike 9 years ago with 3 other people and 3/4 of us didn't make it due to AMS. We went in late Sept and had beautiful weather. I am hoping for the same luck in weather. I figured we would have better luck this time if we camped on the trail. Maybe our paths will cross.
(emphasis mine)

Chickadee and lawnerd:

Acclimation is about the most important factor ensuring a successful summit. Lawnerd's plan to camp one night at the Portal, and a second on the trail is about the minimum required for any sort of acclimation.

If you start up the trail first day, and camp one night, that isn't enough time for most people.

A good acclimatization plan would be to spend one or two nights at Horseshoe Meadows campground -- elev 10,000 -- and maybe doing an easy dayhike for fun, to either Trail Peak or Cottonwood Lakes.  Here's a Trail Peak writeup:  Trail Peak: Warmup / acclimatization hike.  I can assure you, at the end of September, there will be plenty of available space in that campground.