Buttie Box
You need 6 months post final line check which in reality means about a year from joining, a minimum of 1500 factored hours and be approved by the SFO selection board, which in turn means being a good egg, not breaking any expensive aeroplanes, passing sim checks and not inviting crewing to have sex with themselves when they call you off standby. These things get noticed.
You get (roughly) an extra 6 grand PA and another stripe plus a nice letter/email from the grown ups.
As for training, depends on prior experience but generally a year or more in the company so they get to know you, then apply when positions are advertised. You also have to pass the selection board of course but as the ATO grows there are opportunities.
Good luck with selection, its a pretty good number IMHO.