If you are trying to acclimatize, the best sleeping altitude is the highest altitude at which you don’t get sick. I always sleep at the portal in the comfortable bed I built in my car. You couldn’t pay me to sleep in Lone Pine. I started at 1:00 AM in 2010, when I climbed Whitney twice in one day. Otherwise, I don’t think I ever started before 5:00 AM. I need my sleep.