Perhaps you could avoid the which and concentrate on the what and the how?
I mean, when I'm on the night shift, I'm up at 17:30 for my start at 19:00 and leave work at 07:00. Then I'll have a flight from ABZ to LHR or LGW and then check-in which means that I won't be on the international flight before noon, so I'll likely have been up over 18 hours, and very much looking forward to some sleep. But it seems to me that I stand a very good chance of waking to find the cabin in darkness - you have pre-determined sleep times, don't you? And I'm wondering if that's going to cause problems.