Gramps52, 2 mm. of venturi is not a big deal, but the rookies like to kick up drama over it. Don't be concerned; your VM36's will run just fine on a stock 650 motor, although they are a bit more than the bike really needs. Sure they'll deliver a little less down low, but if they're dialed in right you won't feel it in the seat of the pants.
The baselines widely posted for VM34's are also applicable to VM 36's. I know what should go in your carbs for US fuels, but I have no idea what the pumps deliver in Oz. Nor do I have any idea what Bertaut puts in the carbies, but I wouldn't be surprised if he cut a corner or two.
There's an old and very active XS650 club in Oz with members all over the continent. The Australian club counts more experienced performance tuners among its members than any other owners group I know of. A fast Google search will find them.