Hi James,
Welcome to Sydney. Thats a great boat you've got there, Im jealous.
I fish Berowra Creek, launch from the Berowra waters marina which is a great ramp with plently of free parking, pontoon and fish cleaning table. The tinny we fish from is similar to yours and to do well you need to hug the shore and fish the rocks, sunken timber and snags. We use handlines with light line 6-10lbs. Fresh baits such as nippers, peeled hawkesbury prawns and cut mullet fillets work well. Rigs are a simple unweighted hook. Target fish are bream, can't help you with jewies ect.
It is a spot we fish at night only. If your looking for a mate to go fishing with I'd be happy to show you some spots and share costs.
Good luck,
Paul