Oslo is 6 hours ahead of Ottawa
Best overlap: 8:00 AM to 12:00 PM in Ottawa is 2:00 PM to 6:00 PM in Oslo.
Target 8:00 AM to 12:00 PM in Ottawa, which lands at 2:00 PM to 6:00 PM for the Oslo side. Oslo is 6 hours ahead of Ottawa, so the practical overlap is about 4 hours — generous enough for meetings, tight enough to be worth booking ahead.