On arrival at LAX you'll clear immigration and customs including collecting any checked bags and dropping them back off and then reclear security. I recomment reclearing at TBIT rather than going over to T6. Then you'll have a access to the Qantas First lounge and oneworld Business loung in TBIT, the AA Flagship lounge in T4, the AA Admirals Clubs in T4 and T5, and the Alaska lounge in T6. There is a walkway between all the terminals so once you've cleared security at TBIT, you don't have to reclear security going between the terminals. I'd start with the QF F lounge, and then slowly take my time going to T6, with a stop at the Flagship Lounge at T4, and then if you have time left, the Alaska lounge at T6. I wouldn't bother with the ACs or the oneworld business lounge.