[Siri]

Good thoughts. As far as human player-to-coach communication, some sort of sign(s) might be useful. Lunacy (with much simpler communication) had problem enough with less obscured vision.

If we're talking alliance station communication, my initial thought was "Left 1-3" and "Right 1-3". Less ambiguous, but longer to say. A-F seems good too, and likely not too much to process. Frequent fliers or not, most English speakers know without thinking that the first 3 letters are A, B and C. That splits it in half, leaving only 3 choices each again.

As for heights, I'd imagine low/mid/high or bottom/mid/top would catch on quickly. Not sure I understand the need to use numbers for those, especially if there's going to be hesitation on whether to count up or down.