There is no standard 8-to-6 overlap. Someone joins early or late.
Ho Chi Minh City is 12 hours ahead of Austin, which is far enough that a normal 9-to-5 in one city never reaches the other's working hours. One practical option: Austin dials in early while it's still late afternoon or evening in Ho Chi Minh City. Remember that Austin shifts for daylight saving and Ho Chi Minh City doesn't, so recalculate the overlap after each clock change.
| Local time | 12am | 1am | 2am | 3am | 4am | 5am | 6am | 7am | 8am | 9am | 10am | 11am | 12pm | 1pm | 2pm | 3pm | 4pm | 5pm | 6pm | 7pm | 8pm | 9pm | 10pm | 11pm |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Austin America/Chicago | ||||||||||||||||||||||||
Ho Chi Minh City Asia/Ho Chi Minh |
24/7 support sounds great until a P1 ticket falls into the gap between Manila signing off and Dublin signing on. Here is how to design a follow-the-sun support model that actually catches tickets at the boundary. -