I found the key with his waking up early system was that you only fix your waking time, and you stay up (ideally doing something without stimulation close to when you need to sleep) until you're ready to fall asleep within 5 minutes.

I got extra waking time because my body was regulating how much I slept. If I stayed up too late I'd get tired earlier the next day, but in general I dropped my sleeping hours by about 1.