Portland is 9 hours behind Oslo
Best overlap: 5:00 PM to 6:00 PM in Oslo is 8:00 AM to 9:00 AM in Portland.
Target 5:00 PM to 6:00 PM in Oslo, which lands at 8:00 AM to 9:00 AM for the Portland side. The overlap barely stretches to 1 hour, so reserve it for what really needs a live conversation and handle the rest async.