I used to work a schedule called a 2-2-2-80: Two day shifts, come back the second night for the start of two midnight to eight am shifts, come back the second shift to start the 4 to midnight shift. So in essence, 6 shifts in 5 days followed by 80 hours off. You find out very quickly what your internal clock is best suited for, I too am a nocturnal creature and still to this day sleep randomly, I can fall asleep sitting at a desk, then be up for hours at night. So many ideas rushing at me, things seem clearer to me at night.