It doesn't seem like I got much done today. I woke up at 6:40, went to the gym, minyan, home, showered, made lunch and then stalled until 11a. I was in class from 11 until 6, Penn & Inklings from 7-8 (which counts as work as far as the life of the mind) and then back to the department from 9-12, but only working 2 of those three hours. So what is that? 7+1+2, ten hours of work. Not as bad as what I feared. So what would a really productive day look like?
Let's say you get back from minyan at 8:30 and you give yourself an hour to turn around (Email, NYT, shower, make lunch, FB). Work from 9:30-6:30 an hour and a half for dinner and then another four hours at the department. That's 13 hours, which is about the upper limit over any non-small stretch of time. The day seems like more than 13 hours can be squeezed out of it, but I just don't think it can, absent serious quality of life compromises.
If you were crazy and had your meals served to you at your desk you could probably get six hours of sleep, an hour for turn around (wake up, shower, get into the apartment, take clothes off), an hour commute and a half an hour for davenning leaves 24-8.5, fifteen and a half. So the margin between productive and paralysis is only 2.5 per day. There just really ought to be more time.