Copenhagen is 7.5 hours behind Adelaide
Best overlap: 3:30 PM to 6:30 PM in Adelaide is 8:00 AM to 11:00 AM in Copenhagen.
For the smoothest call, aim inside 3:30 PM to 6:30 PM in Adelaide, i.e. 8:00 AM to 11:00 AM in Copenhagen. A 3-hour overlap gives you a workable daily window; aim for earlier in it to avoid clipping the end of someone's day.