Thanks for the suggestions, guys.
I understand the discussion of the initial merge, but to be honest I'm not sure how much applies. I had framed the question focusing on the endgame, and the initial setup info was.....not at all exact.
The whole thing developed REALLY fast. I had started roughly east of the base, out over the water and to the south of a fairly busy furball. There were maybe 15 cons in the ball, and another 10-20 in various stages of entering and exiting it, but in the general area. I topped out a barrel roll, used airelons to reorient, and cut down through the furball. I chose a target, rolled a bit, and pulled up to fire for the kill at somewhere between 1-2K. Then roll, nose down, and prepare to exit to reset.
As I popped out of the furball, I spotted the daisy chain of the Spit XVI and its pursuers. They had been completely away from the ball, off towards those hills that line the NW edge of that base -- and he just happened to break from THEM by running in my direction. The Spit was as first so low that he was a dot, no icon, and I actually saw the friendlies first. There was no way to track him "all the way", because in furball terms he was in teh next county until I arrived!
Your comments about the merge are good, but since the "500" was pulled out of my ...hat.... I can't say how successful an aggressive move would have been. I do know that I didn't FEEL threatened as he passed, and the more I think about it 500m would have felt like a...situation... to me. It may have been farther away.
The core of my mistake there was in threat assessment, though, no doubt. I discounted him the same way a fullback stops seeing a tackler that just can't reach him in time. I continued to track him, and saw him reverse. It's a subtle difference, but I still believe my screwup was in Energy assessment, not in SA. After he had picked me, I let wishful thinking delay an aggressive move. As I said at the start, that was mistake #2.
I still cant bring myself to film every engagement, because I end up with huge long lists of unidentified "FilmXX" that I have to examine at some future date. Too close to work for fun! May have to consider it though, as I keep trying to hone the sharp edge.
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Widewing: didnt see your post till this am, so didnt make it last night. Will you be there again tonite or tomorrow?