#2 - Some researchers think there is wide variability in the optimal amount of sleep. Some even think that you can get too much sleep. The thing to do is to pay attention and experiment. I sleep in two sessions, one 4 hours, the second three. Getting more sleep makes me feel a little worse. The good news, is that there are cheap sleep monitoring smartphone apps.
I completely agree as a bimodal sleeper myself. If I sleep over 7 hours in one session I feel terrible, much worse even than if I would have only gotten 5 hours of sleep that night. I usually sleep 5 hours a night and take 2 and half hour nap. You just have to figure out what works for you.
What has worked for me in the past was going to bed at 10:30pm and waking up at 5:30a - 6:00a. Now that summer has started I've screwed up my sleeping pattern that I'm slowly trying to get back.
