Hey Sam,
You could try tying up some of these mate, using regular red Kevlar you should be able to source locally from your tackle stores, or on the web ( we stock it, but I'm sure someone closer has it too ). This method basically uses 4 strands rather than just 2 for the Assist giving you extra bite protection:
http://www.gtpopping.com/forum/index.php?topic=2098.0Alternatively, as suggested by Brandon in the thread posed above, you could use the Split Ring-Swivel-Split ring method as shown below, pic courtesy of Matusani San, and is his preferred rigging method for Doggies.
As for the leader set up.... seems most widely avoid wire, and rather go with heavy flouro....
I think, much like with GT fishing, chasing big Doggies, or landing them should I say, involves a large amount of luck..... I hope you have a bunch!