Portland is 13 hours behind Karachi
There is no standard 8-to-6 overlap. Someone joins early or late.
Set against a 13-hour difference, Karachi and Portland run their workdays on completely separate schedules. Block a single recurring off-hours slot that both teams agree on, rather than negotiating a new awkward time every week. Don't be caught out by clock changes — Portland observes daylight saving and Karachi doesn't, so the offset varies by an hour through the year.