Quick note to say had really good experience with QANTAS (again) getting my gear to WA from QLD and back, no easy task this year with 3 kids under 12 and a +12 week old!
They even helped carry by board to oversize! or at least tried!
Kids all used carry on Bags nothing in the cargo, that allowed a 3 bags + board bag and rig bag.
no extra charges nothing, key Number is 32kg, kit bag has to stay under that which isnt that easy, the other key factor is rain, you dont want any of it and ensure board, sail etc is 100% dry before packing to keep weight down.

I have lucked it with the rain issue on all my trips, but the more I think about it the more I relaise it could throw everything pear shaped!