Don't want to be a party pooper here, but I would not recommend running a full quart low on oil. I realize that running clockwise will keep oil near the oil pump pick-up, but will it always? Best to just run the separate breather line.
You will also be running into trouble with your fuel pump. As the pulse is taken off the left side of the block, the pulse line more likely than not will someday fill with oil, thus killing the pulse signal to the fuel pump. I would suggest plugging the pipe-tapped hole on the left and move the whole system to the right side of the block.
Another issue may be that racing "Down Under" means that the mower is actually upside down, in which case, the engine should immediately be shut off while you grab several beers to aid in thinking the problem over. Foster's, anyone?