Sorry for the confusion everybody... I will have 2 separate tickets. Currently delta first class from SAN to LAX with an allowance of 2 bags @32kg, and QF economy on QF 94 with an allowance of 3 bags @23kg.. (request for upgrade to business).. Should request fail I gather from replies that QF will almost certainly charge me x 2 heavy bags- even though total weight will be less than my allowance...
My other option is to book an award AA flight in first class from SAN to LAX with an allowance of 2 bags @32kg- with the expectation that they would through check my 2 bags all the way through to Melbourne as per the one world alliance policy where they treat separate tickets like one single ticket for one world connections.. My question is here can I expect to run into issues at SAN check in with AA- as my AA and QF allowance is different- even though total weight will be less..