German to English Art/Literary Music

“An der querformatigen Handschrift fallen zunächst drei Besonderheiten auf:
…
2. Die zahlreichen, nur mit einer Satzüberschrift versehenen Leerseiten. Bei der Konzeption des Orgelbüchleins hat Bach insgesamt 164 Satzüberschriften eingetragen, von denen aber kaum ein Drittel realisiert worden ist.“

I´m not sure what to do with “Satzüberschrift” here. The Orgelbuchlein actually contains some 60 chorale preludes (as I learned to call them as a student organist). I don´t like to refer to these as “movements”, since this for me implies parts of a larger work, whereas the Orgelbuchlein is not a unitary work, but a collection of many small pieces. “Setting" is my next thought, but chorale preludes are not really settings. And “piece” is too informal for this use.

And then there´s the “-überschrift”: is that "title" or “heading” or what? (It is always the name by which the chorale is/was known, usually, if not always, the initial words.)

Any advice, guidance or assistance will be greatly appreciated.