keyboard staff to 4 part chorus?

I had never looked at that. Very cool.

John, this will work ... but you'll still have to manually fix a lot. Pay very close attention to the handbook page that underquark linked to.

Your music has both multiple voices and chords within each voice. Those have to be exploded separately. When I did it to your piece, I first exploded the multiple voices each to their own staff. Then, for the staves that had chords, I expanded the chords onto multiple staves. This meant that the alto part, for example, is sometimes scattered among two or three staves, and other times is correctly all on one of the three new staves. But it looks like the soprano part is correct: all on the original first staff.