Riyadh is 1 hour ahead of Copenhagen
Best overlap: 8:00 AM to 5:00 PM in Copenhagen is 9:00 AM to 6:00 PM in Riyadh.
Target 8:00 AM to 5:00 PM in Copenhagen, which lands at 9:00 AM to 6:00 PM for the Riyadh side. That's a roomy 9 hours of common time each day, so finding a slot that suits everyone is rarely a problem. For part of the year the maths changes: Copenhagen observes daylight saving, Riyadh does not, shifting the overlap by an hour.