I am not familiar with the ADL Customs set-up for checking / stamping documents for the checked wine. It might be worth a phone call to ADL airport - Customs and specifically ask them whether they can or will do it. Otherwise, you'd face checking the wine to SYD, claiming it at T3, carting it to T1 ground floor Customs for their checking / stamping process before re-checking for your onward flight. Then claim GST refund airside T1 (allow 30 minutes for this if things are really bad with the queue).

If ADL can't / won't stamp the paperwork, I don't really think you have enough time in SYD to do all that I suggested above - and that doesn't even allow Flounging time

Good luck with the wine shipping - and hope it arrives intact - and hope you enjoy every last drop!

I'd suggest the QF seamless transfer rather than the Opal card / train process.