I'm out to grass, but as nobody else has answered.
The roster was previously 4 on two off but is now in the proces of being changed. You could try requesting furthr info
here.
Overtime as such is not generally scheduled, you can be requested to cover extra duties or to follow compulsory courses. Compensation can be taken as extra paid leave.
Travelling days (Max 2 per year IIRC are dependent on the distance to your place of origin)
I think with the creation of the O grades shift allowance has disappeared.