8:30 or 9:00 East Coast USA time so that our friends on the West Coast have a reasonable late-afternoon / early-evening hour. Tentatively I would suggest Tuesdays at 8:30 for no reason in particular. Please let us know your suggestions for alternate dates and times.
That's around 3am in Central Europe! For our participants staying in Europe and Africa it would be worth thinking of a second panel (and theoretically a third for the Far East and Australia).