Living in Australia, I had a phase of working for US clients that often required early morning meetings (7am), but then the rest of the day was up to me. I'd often do something a bit similar: Alarm for 6.50, slam down a bowl of cereal, and on the call at 7. Finish the call at 8, a bit of follow up stuff, then wander around in a daze until 11am, when I'd do a couple of hours work.

Then I'd take the afternoon off, and settle back down to work around 5, and do my most productive work from around 7 to 11pm, then bed.

I didn't love the early meetings, but I did like the bit where no one would bother me during my work day because they were all asleep.

The trickiest times were when I had to catch both a 7am US west coast meeting, and an 11pm US east coast meeting on the same day. Hard to go straight to sleep after an intense meeting.