Zurich is 12 hours ahead of Honolulu

There is no standard 8-to-6 overlap. Someone joins early or late.

Honolulu and Zurich are 12 hours apart, and that gap is wide enough that their normal 9-to-5 workdays never quite touch. If you meet regularly, fix one off-hours slot and rotate it between Honolulu and Zurich so the burden doesn't fall on one team. Remember that Zurich shifts for daylight saving and Honolulu doesn't, so recalculate the overlap after each clock change.