Good points Mwenenzi. I'll credit my QF flights to AA by preference unless I wind up in a non-earning code in which case I'll credit them to QF. (Though my AA platinum ends very soon and I don't know whether they'll soft-land me to gold or not.) Meanwhile, I'll join OZ with a view towards crediting my future *A flights there and hopefully keep *G in my back pocket. Exact details can be figured out once I'm more familiar with my new employer's travel policies.

Thanks for your help! ^