FOTW, quoting the Australian gazette entry "The Gazettal of "The Royal Australian Air Force Ensign" of May 1982:
"the Southern Cross as a whole is angled away from the fly with the "Gama Crucis" positioned as for the Australian National Flag and "Alpha Crucis" positioned 1/6 of the width of the fly from the middle line of the fly and 1/6 of the width of the fly from the bottom edge."