I think what Luke is telling you is pretty sensible. If you find structure, current and bait, you shoould find GTs and among the GTs, it is likely there will be some bigger fish among them. You don't grow that big if you're stupid so big GTs tend to be just that little more cautious and smarter than the school fish.
It's very hard to specifically target big fish in Australia and it isn't because they aren't there. The breaksea spit off Fraser Island is a legendary location but takes a lot of expertise in terms of times and conditions. Personally, I suspect there are more huge fish hanging off the east coast of Australia than anywhere else in the world and to me, that is a matter of common sense. It's the biggest stretch of reef in the world and the number of juveniles that can be found in enormous numbers in some areas is amazing. Small fish become big fish - eventually.
The problem is there are loads of smaller fish and that makes it very hard to specifically target the bigger fish. In New Caledonia which is surrounded by the second biggest coral reef in the world, the former operator there, Le Poisson Banane, managed to figure out how to target big fish in deep water off the outside edge of the reef. This form of fishing though takes a lot of patience, not to mention energy to persist for long periods of time with big lures. I don't know anyone who targets this type of area in Australia for the simple reason that the outside edge of the barrier reef is a long, long way out and for the most part, it doesn't drop off immediately to very deep water which is where I suspect a lot of the really huge fish live in.
One of the Nomad Sportfishing guides, Glanville Heydenrych has figured out a way to target really big fish out on the reef in shallow water and having fished with him on numerous occasions, he knows what he is doing. The problem is, hooking it is only the beginning of your problems. Big fish, shallow water =
The area around the Arabian gulf seems to produce more big fish for numbers of fish caught than anywhere else. Not really sure why although I suspect they may be transient fish that are migrating through at specific times of the year.
