Adelaide is 7.5 hours ahead of Zurich
Best overlap: 8:00 AM to 11:00 AM in Zurich is 3:30 PM to 6:30 PM in Adelaide.
The overlap falls at 8:00 AM to 11:00 AM in Zurich, or 3:30 PM to 6:30 PM if you're in Adelaide. You've got a decent 3-hour window. Set a recurring time near 8:00 AM in Zurich (3:30 PM in Adelaide) and stick to it.