Shanghai is 13 hours ahead of Houston

There is no standard 8-to-6 overlap. Someone joins early or late.

The 13-hour offset between Houston and Shanghai means there's no point hunting for a 9-to-5 overlap — there isn't one. Expect compromise: someone in Houston or Shanghai will need to take the call outside the usual 9-to-5, so share that load. Finally, Houston observes daylight saving and Shanghai doesn't, so this window shifts by an hour for part of the year — recheck it each spring and autumn.