I cannot emphasise ENOUGH how good what you are doing is, D. I'm much the same, I don't usually get much sleep, but I find that when I DO, my recall increases drastically, and I even get the occaisional LD. When I CAN, I try to keep to a similar schedule as the one you posted: Roughly, 10pm sleep, 6am wake, or sometimes 7pm.

Good luck with your schedule! I'm gonna try to get my own schedule back where it should be too... Sleep schedule is a much underrated way of getting decent recall, in my opinion.