Blah. I have to coach this occasionally (mostly they're somewhere below L4 though so they're not at a point where they're really ready for much anyway...once they are stronger there are coaches who know what they're doing) and added to the fact that I have absolutely no idea what I'm doing (true story...pommels are a mystery to me), none of them are even seemingly capable at it anyway. I don't blame them since I'm not that interested and also probably couldn't even be a L4 on this event if I tried.
I just make a circuit with a bunch of random stuff that seems good to me, although I can't really advocate any of the specifics since again, not all that confident in what I'm doing, but I'm sure you can come up with much better exercises than me. If I just have them go one at a time, then each one ends up taking too long when I try to make corrections and it's just not good. I include a body tightness station like be in push up position, straight arm lifts, or something like
these positions (but easier than walking that far). I mean, that looks like a pommel/mushroom position to me. I don't really know.
But then (I do this with beam too) sometimes at the end I have everyone sit and watch everyone's best attempt. Then they usually try harder to improve. I would also probably keep a chart...they can keep it, you can keep it, it can be posted on a board by the station, whatever. If they can only do one circle, record how many successful repetitions they did each practice (you could even break this into attempts and successes if necessary) out of a target, say 10. For the first "phase" they can try to improve their number of successful attempts out of 10, or get to 10 successful attempts. When you decide they're ready for the next "phase," design a harder phase with another focus (perhaps 1 1/4 circle or something, I don't know what is realistic). You can also add an incentive like whenever someone hits x number for the day or moves up a number, they get to make a mark on the board/put a chip in a bucket, etc, and when you have so many marks or chips, they get to play a game during practice or have open play for a period of time. To break it down into individual awards, perhaps the individual contributing the most could be the one who gets to choose the game, or whatever.