[at the conclusion of discussion of angles vs. energy tactics]:
"With any of the tactics outlined here, whenever the opponent makes a forward-quarter approach, consideration should be given to attempting a short gun burst at the pass. Although this is generally not a high-percentage shot, it is useful in establishing offensive and defensive psychological sets between opponents, and it may disrupt the adversary's game plan. The pilot should assess the possible value of this shot against its effect on his own maneuvering requirements and ammunition supply."
Shaw, Fighter Combat, p. 112.
I think I'm mis-construing what you all are referring to as the HO. My point is that it is useful to put some rounds at the bogey if he's in front of you- not that you necessarily maneuver for a HO kill at the merge. Knowing your opponent is going to shoot you in the face at the merge can help the pilot establish separation or lead if desired, depending on how he maneuvers and what kind of fight he's going for.
Just my thoughts. I guess we can see how I feel a year from now about this tactic.