Houston is 7 hours behind Vienna
Best overlap: 3:00 PM to 6:00 PM in Vienna is 8:00 AM to 11:00 AM in Houston.
If you set up a recurring sync, 3:00 PM to 6:00 PM in Vienna (8:00 AM to 11:00 AM in Houston) is the natural home for it. Around 3 hours of overlap is enough to work comfortably, as long as meetings don't drift to the end of one team's day.