Call me backwards, old fashioned or whatever you like, but I don't really trust the idea of the 61 pt auto point selection.You're none of those things and I absolutely hate 61-pt for One-Shot AF because it always seems to select the wrong point.
OK, I'm not alone here
For AI Servo, however, you get to select the initial point, and once you place that on the subject, lock on, and begin tracking, the subject is now tracked throughout the entire AF sensor, not just the zone.
The difference between auto selection in One-Shot and manual pre-selection in AI Servo is the key here.
I will have to work on that some more, because the 61-pt auto seems to go "all over the sensor" for me, even in AI Servo - seemingly regardless of my pre-selected point.
But on to my experiences last night:
As suggested, I did a Clear All Camera Settings and Clear All Custom Functions on the body to get rid of the BIF-optimized settings that I've previously tried and set up the camera to my preferences (BBF, direct selection of AF point on the joystick, AFMA enabled, etc).
When starting to shoot, I found that the AF was doing something really weird on me: it would choose the center AF point for final focus even if I had set the AF point to a different point. After desperately trying to change settings on the fly and understand what was going on, I caved in and gave the body another Clear All Camera Settings. That fixed it. Clearly, I don't understand well enough how all those AF settings work together, and I didn't have the time to sort it out the systematically at the time.
I used AI Servo, High-Speed continuous and shooting short bursts of 2-3 shots at a time. I would vary keeping AF engaged while following the model walking down the runway to stopping/re-acquiring AF with the BBF. Same when they paused at the end of the runway.
AF selection points:
When using both Zone and 61-pt auto-selection, I found that it focused on the "wrong" points, just like mackguyver is describing. I didn't find much difference between the 5 & 9-pt expansion modes, where I had more lenience about following the model with the selected AF point, than when using a single point. No surprises here
AF mode and adjustments:
With the resets, I went back to AF Mode 1, without adjustments. Later I tried to change the Focus/Shot priority from both/both to focus/focus, but since this doesn't seem to be registered in the EXIF, I am unable to distinguish between the two settings. Next time, I should shoot to a new card folder when changing modes.
I didn't spend too much time on chimping during the show, but my impression is that chimping is only good for sorting out the glaring misses: I have to get the pictures up on my computer monitor at 50% or 100% to sort out the shots where the focus is almost there vs the shots where the focus is just nailed.
Looking at several series of shots (each model walking down the runway), it looks like that the tracking speed / snap-on speed is not up to my expectations. This could be the start of a longer investigation, since chimping doesn't seem to be good enough to tell the difference.