Philadelphia is 6 hours ahead of Honolulu
Best overlap: 8:00 AM to 12:00 PM in Honolulu is 2:00 PM to 6:00 PM in Philadelphia.
Keep meetings inside 8:00 AM to 12:00 PM in Honolulu — that maps to 2:00 PM to 6:00 PM in Philadelphia. You share roughly 4 hours a day. That's enough for regular meetings, but treat the window as prime time and guard it. Finally, Philadelphia observes daylight saving and Honolulu doesn't, so this window shifts by an hour for part of the year — recheck it each spring and autumn.