Nairobi is 7 hours ahead of Montreal
Best overlap: 8:00 AM to 11:00 AM in Montreal is 3:00 PM to 6:00 PM in Nairobi.
The overlap falls at 8:00 AM to 11:00 AM in Montreal, or 3:00 PM to 6:00 PM if you're in Nairobi. You get roughly 3 hours of shared time, so aim for the middle of that window to keep the call comfortable for both teams. Just remember Montreal changes its clocks for daylight saving and Nairobi doesn't, so confirm the overlap whenever the seasons turn.