If you've got jet time and company jet time it'll be less than a year to command.
Great for the guys in Australia for a secondment and some command time.
If you're not on the Australian seniority list, have an exit plan and a return to Australia plan. Once you're an expat it's very hard to get back in. In fact the logical progression will be further afield from Vietnam.
The sandpit becomes very laborious when it's time for a family and the coffers are full.
There's no place like home.