Prague is 8 hours behind Melbourne
Best overlap: 4:00 PM to 6:00 PM in Melbourne is 8:00 AM to 10:00 AM in Prague.
Target 4:00 PM to 6:00 PM in Melbourne, which lands at 8:00 AM to 10:00 AM for the Prague side. The overlap barely stretches to 2 hours, so reserve it for what really needs a live conversation and handle the rest async.