Wellington is 4 hours ahead of Beijing
Best overlap: 8:00 AM to 2:00 PM in Beijing is 12:00 PM to 6:00 PM in Wellington.
For a call that suits both sides, look at 8:00 AM to 2:00 PM in Beijing / 12:00 PM to 6:00 PM in Wellington. Despite the 4-hour difference, a 6-hour overlap keeps things simple and gives both teams breathing room. Because Wellington and Beijing don't both observe daylight saving, plan to re-check the overlap around March and November.