Thanks for the feedback! In considering this further, the comment about muscle memory playing a part seems on-the-dot, and in discussion with some more experienced MNKs in my FC on the same subject, it came to light that thinking in terms of a "rotation" might have been part of my problem. A rotation implies a nice easy pattern, but here there's just so much timing-based stuff to juggle around while also contending with fight mechanics that the best results are always going to come from adaptability rather than fixed choreographed precision. This ain't no dance routine.

Incidentally: Is there a popular way to set up one's hotbars for this job?