Geneva is 6 hours behind Ho Chi Minh City
Best overlap: 2:00 PM to 6:00 PM in Ho Chi Minh City is 8:00 AM to 12:00 PM in Geneva.
If you set up a recurring sync, 2:00 PM to 6:00 PM in Ho Chi Minh City (8:00 AM to 12:00 PM in Geneva) is the natural home for it. Geneva is 6 hours behind Ho Chi Minh City, leaving about 4 hours of daily overlap — enough for most meetings if you don't leave them too late in the day. Remember that Geneva shifts for daylight saving and Ho Chi Minh City doesn't, so recalculate the overlap after each clock change.