Lagos is 1 hour behind Bucharest
Best overlap: 9:00 AM to 6:00 PM in Bucharest is 8:00 AM to 5:00 PM in Lagos.
For the smoothest call, aim inside 9:00 AM to 6:00 PM in Bucharest, i.e. 8:00 AM to 5:00 PM in Lagos. 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: Bucharest observes daylight saving, Lagos does not, shifting the overlap by an hour.