Shenzhen is 7 hours ahead of Prague
Best overlap: 8:00 AM to 11:00 AM in Prague is 3:00 PM to 6:00 PM in Shenzhen.
If you set up a recurring sync, 8:00 AM to 11:00 AM in Prague (3:00 PM to 6:00 PM in Shenzhen) 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. These times hold for most of the year, but Prague's daylight saving (which Shenzhen doesn't use) shifts them by an hour twice annually.