Best overlap: 1:00 PM to 6:00 PM in Brisbane is 8:00 AM to 1:00 PM in Islamabad.
The sweet spot is 1:00 PM to 6:00 PM Brisbane time, matching 8:00 AM to 1:00 PM in Islamabad. You've got a decent 5-hour window. Set a recurring time near 1:00 PM in Brisbane (8:00 AM in Islamabad) and stick to it.
The US to Australia gap runs 14 to 19 hours depending on the month, and someone is always in tomorrow. Exact overlap windows for every US coast, the double-DST trap, and a rotation rule that keeps it fair. -