Stockholm 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 Stockholm.
If you set up a recurring sync, 3:30 PM to 6:30 PM in Adelaide (8:00 AM to 11:00 AM in Stockholm) is the natural home for it. You share roughly 3 hours a day. That's enough for regular meetings, but treat the window as prime time and guard it.