Best overlap: 11:00 AM to 6:00 PM in Riyadh is 8:00 AM to 3:00 PM in Manchester.
Book within 11:00 AM to 6:00 PM Riyadh time (8:00 AM to 3:00 PM in Manchester) and both teams will be at work. That's a roomy 7 hours of common time each day, so finding a slot that suits everyone is rarely a problem. Note that Manchester follows daylight saving while Riyadh stays put, so the times above drift by an hour seasonally.
London to New York is five hours apart, except for the five weeks a year when it isn't. Exact overlap windows for every US zone, the 2026 DST mismatch dates, and where to put the recurring sync. -