Another challenge is that I'm trying to do multiple types of matching at once - not just the motion, but also the lyrics and the beat and the story arc of the vid overall.

This is one of the biggest challenges, juggling everything and trying to make judgment calls down to the microsecond sometimes. Which is why I like the focused structure of these exercises. Like trying to learn an entire piano concerto, but movement by movement, so that by the end all the pieces come together into a beautiful whole.