Melbourne is 8 hours ahead of Copenhagen
Best overlap: 8:00 AM to 10:00 AM in Copenhagen is 4:00 PM to 6:00 PM in Melbourne.
Shoot for 8:00 AM to 10:00 AM in Copenhagen; your Melbourne colleagues will see that as 4:00 PM to 6:00 PM. Melbourne is 8 hours ahead of Copenhagen, so common hours are scarce (about 2 hours). Lock the slot, keep it short, and follow up in writing.