Nathan, firstly, you should be reminded that catching bugger-all in the Whitsundays is still infinitely better than struggling along at work!
Mate, I reckon you should pull out the light gear.......from my experiences up there in that great part of the world, as soon as you start flinging lures around with lightweight gear, the big GT's magically (ironically!) switch on.
Then once you've got the fish all amped up, go back to elephant guns.
Of course, using the lighter gear might increase your chances of bycatch (queenies, spaniards, trout etc) too.
What's the tidal movement like up there at the moment? On our Whitsunday trips, we've found that the less tidal variation there is, the harder it is to find feeding fish. I am going up there in about 8 weeks time, and we've timed our trip for the lead up to full moon, so hopefully that sees some good water flow and fish activity.
Let me know how you go.
Cheers
Angus