I have to semi agree with the statement that you shouldnt shoot at an opponent HO until after the initial merge.
IE. Two planes each flying hell bent for leather towards each other, PASS each other and either loop, turn or otherwise try to out position each other. If one of them gets a snap shot off and it just happenes to be HO then let the chips fall where they may. If you lost, get a new plane and try again, if you won try to be humble about your victory and move on...either way MOVE ON! All this crying about what is a HO is ridiculous. Two planes flying towards each other....Thats HO. If you cant figure that out then maybe you should go play barbies dream house with your dress on or something.