I am 1K this year, trying to book a flight SFO-SYD-BNE the end of Feb.

the seat map shows econ has 4 seats left. I searched Business class there are more seats available.

While I don't trust the seat map occupancy to be 100% accurate, does that mean a good chance the SWU will get approved? And do I need the ticket to be in a certain ticket class to use the SWU, I cannot seem to find this information.

Also does the SYD-BNE by virgin blue going to restrict me from using SWU, I don't remember if their flights have 2 class or just 1.