Reporting back, in case any of this is of interest to anyone other than myself.
I've been rehabbing a hip issue, and gearing down seemed like a good measure to take some pressure off, so I've been running a 56/16 the past two weekends in practice sessions. Feels great, much easier on my hip. Matter of fact, I'm not feeling any significant pain while riding the track bike now, only when walking...which is great, it only hurts when I walk. That's like when I've had broken ribs, and someone asked, "Does it hurt much?" and I'd say, "No, only when I breathe."
Anyway...The interesting thing is that I'm running 136-137 rpm (max) in the 200 training runs, higher than I thought I was able to. It feels like I'm maxed out on cadence in this gearing, but perhaps that's just because I'm in experienced and need to work on smoothness and what I would call foot speed. (I hear people talk about leg speed, but in my mind, I'm visualizing food speed.) I wonder when it makes sense to go one tooth smaller in the rear, are there any general guidelines? For example, if I can raise my max rpm in this gear up to 140, would that indicate an improvement in mechanics, at which time, moving to a smaller cog would be reasonable, because I'd bring better spinning technique to the table to get the most out of that next heavier gear?
I'm trying to apply some logic and goal-setting to working my way into heavier gearing little by little. I sort of rushed into it in the Fall, and that's certainly what contributed to firing up my injured hip. The combination of lack of diligent training, lack of strength to turn the heavier (56/14) gear set efficiently, and lack of spinning technique all culminated in imparting serious torque into my hip joint instead of distributing the workload over the muscle groups surrounding it. Good lesson learned. And it's now forced me to learn how to become a better spinner, so I feel fortunate; I'm taking a step back to learn important fundamentals which I wasn't necessarily putting enough time or focus into.
If I can establish a sensible goal for improving spinning technique, and reach it in some basic, recognizable way, I'll move from the 56/16 to the 56/15, and then 14, with the ultimate goal of trying the 13 without blasting my hip apart. The objective is to hit 120 rpm in the flying 200 in that gear sometime later this year. Not convinced that's possible, but I'm going to work toward it and we'll see what happens.