Even though Canada is cheaper than the UK for your start point at the moment, it's much more expensive than other places in Europe, including the Euro zone, for both A- and DONEs. See WearyBizTrvlr's recently revised Excel spreadsheet referenced in an earlier thread. Also note newcx12345's comments about limited stopovers in continent of origin. Don't know how long you'd want to spend in N. America, but six segments but 2 S/Os sounds like a lot of sleepless nights to me.

Of course if you start in Europe (say IST or even GIB) you'd need to manage your stopovers in Europe, too - London for one, maybe, then?

One thing to consider is eastbound v. westbound. You might look at something like (Europe)-LHR-Oz-Asia-(or -Asia-Oz)-N. America-Europe which wouldn't give you the mid-trip break at home your initial itinerary had, but which would you to make the most of your mileage accrual aims given the possibility of longish Asian and American routes.