I haven't caught a metro mack either but it sounds to me like you're putting in the hours and doing all the right things from what I've read. There are plenty of people who say their biggest mackies come from trolling baits so I think gardies might be the right way to go.

There are a number of different rigging heads that you can use for gardies. Mold Craft do a Hoo Hooker Head for skipping baits that also create a bubble trail. I've used these and caught black marlin in Exmouth. Richter do a weighted Bait Runner that gets your bait down deeper. All of these are designed to stop the gardie blowing out its guts and becoming useless. If you stitch some bait rigging thread you can make them last all day easily.

Good luck!

 unintentionally.  Both on drifted mulies where I had too lighter running sinker and they were way up in the water column.  Oddly this is how I fish for them out of Dampier and Exmouth .....never had much success on lures.  I now always have a floater when out drift fishing hoping for another.  APRIL May are the months I hooked up 

whether you are trolling baits or lures. When I lived up north I would target sails using gardies as skip baits. I never caught a mackie on a skip bait. Put the gardie on a downrigger, bingo mackies.
The pros would to troll lures / baits using plastic coated wire handlines (like you see on a washing line) and this provided the depth required.

 In that 30 m depth of parkers, but deep divers are ny preferred go to.

My theory is the water temps around Perth are fair bit cooler than what they are used to so their behaviour is a bit more "sluggish" around here than what you'd expect up north, meaning you have to work a bit harder and think outside the box. Obviously plenty get caught every season the more traditional way of trolling hardbodies but to increase your chances in Perth definitely consider trolling dead baits and when you find some more likely looking areas ie. drop offs with consistent bait, high water movement, flying fish and obviously free jumping mackerel, then it's worth having some livebaits out. You can't cover the ground as much fishing with livebaits so you really have to find those likely spots first and commit to them rather than just fishing blind otherwise you will more often than not start to doubt yourself as you watch the rod tip waiting for that bite. Over the last 8 years I have done well fishing live herring but the last 2 seasons I have leant towards 30-45cm tailor as baits as they throw off a really good presence in the water, similar size skippy would be just as good if not better with those large silver flanks but I've yet to give them a go.
Good luck and let us know how you get on. I'll see if i can get some photos uploaded from the last few years

He is the metro mackie Yoda (the good one from the first 3 movies).

he keeps them quiet, but that guy has caught more metro mackies than i've had wanks over Taylor Swift. 

How's those baits .. like there been 

cut with a knife .. cheers pirate 

 I have a mate that lived in karatha for a lot of years and he swears by mullet hook in the back and one through the mouth a bean sinker on the nose and he reckons they troll good and the mackies love them.

 water temp over 25 degrees...

Do we think it's worth a troll on the back of the five fathom with the warm water temps we have at the moment?

Or best to head out a bit wider towards Rotto?