Thanks to Virginia, who reminded me that I can use one rein to pull her into a circle which disengages the hindquarters and takes away her power to buck, I was able to stay in the saddle for the next round of crow-hops and Starbuck learned a valuable lesson: bucking doesn't get her out of having to work. After those two brief rebellions, she calmed right down and did fine. I can tell she feels a lot less constricted in the big arena, her strides were much bigger and freer and just the fact that she was confident enough to buck with me on top of her tells me she's feeling stronger and more balanced carrying my weight. Also she didn't seem to have any urge to run around like a chicken with her head cut off and responded really well to the reins so I feel confident about riding her in the big arena from now on.
Here's the video of the entire ride, it's too bad that most of the rodeo action is either off-camera or blocked by other horses, but you get the general idea. I chickened out trying to get her to trot, so after a couple of strides I gave her a break. Next time I'll be sure to have my crop with me so I'm not teaching her to ignore my leg cues.
Just a note to remember for next time: I dewormed Starbuck today too with Eqvalan Duo, I think that this next time I'll wait 3 months and use a less powerful wormer. I'd also like to do a fecal analysis, when the vet comes to vaccinate her I'll ask her about it.