Here are a few things I can clarify.
I know Brett. He is an animal. His wife was telling me at Barkley that during the entire time he sweats profusely. This means he can move just under his lactate threshold for at least 54 hours. Seemed about the same on the JMT as the last day he fell apart and "just hiked" it in to the finish. His previous 2 1/2 day pace was much quicker.
As far as his sleep schedule, I agree, but after his 6 hours of downtime, he virtually caught and passed Hal and Mike until Reds Meadow. The extra sleep must have done some good?
As far as Michael Popov. He was a big guy, 6'2" and 190 at the time of his attempt. He had a very solid hiking pace but it also took a lot out of him to burn that powerful engine. After 19-20 hours he needed that 4-5 hours of sleep. Without it, he would slowly go down hill. I had done a few events past 24 hours and I could keep up the pace and pass him in the end.
Problem was, he would be good to go with that 4-5 hours of sleep.
I let Krissy and Jenn know what I thought about sleep.
I said the best way to go is to just eat with the resupply and then have one of them head out with you and some sleeping bags.
After an hour or so of some uphill hiking you are going to burn off your anxiousness and the good 1,000 calorie meal you ate and be extremely tired.
I thought they should have gotten 4 hours the first two nights and 3 the last.
Getting sleep and being fast is much faster than a tired zombie walk any day.