Martin,
I used 2 types of flies for 90% of my Cape York fishing, clouser and gurgler.
Kinkyfibre clouser and gurgler on 1/0 or 2/0 hook. I recomment the Gamakatsu SL12S.
Gurgler are great for queenies and giant herring.
Clouser caught everything from Snub-nose dart, barra, queenies, jacks, trevally, giant herring, coral dwelling ooglies and cobia.
Cobia on 2/0 Grey/white kinkyfibre clouser
You could throw in surf candies for tuna, bendback, pink things, deceivers(to keep Max happy) for Barra. Flashy profile for G.T.
The fish up there will eat just about anything you throw at them. Just get a fly in front of their nose.
Wes