Panama City is 5 hours behind Reykjavik
Best overlap: 1:00 PM to 6:00 PM in Reykjavik is 8:00 AM to 1:00 PM in Panama City.
The overlap falls at 1:00 PM to 6:00 PM in Reykjavik, or 8:00 AM to 1:00 PM if you're in Panama City. You've got a decent 5-hour window. Set a recurring time near 1:00 PM in Reykjavik (8:00 AM in Panama City) and stick to it.