Madrid is 12 hours ahead of Honolulu
There is no standard 8-to-6 overlap. Someone joins early or late.
Set against a 12-hour difference, Honolulu and Madrid 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. For part of the year the maths changes: Madrid observes daylight saving, Honolulu does not, shifting the overlap by an hour.