HARMONY does support the abc line break option, and puts a new line wherever specified. It also has a line break command in its own native tune format (see Command @F)

What it does NOT do is try and align the bars in successive lines of the score. This could cause problems if one bar has a lot of short notes. But as I said, I could provide this facility if required, and you would have to live with any overflow caused. There is also a HARMONY (@) command to modify the space between notes, but currently you have to edit the text of the voice files to implement this. I could perhaps add the facility to compress a group of selected notes to the program menus.

Note also that HARMONY supports the abc PART specifications which are useful for dance music.

You only need to put in each of the parts once, and then the playback will generate them according to the formula supplied (see abc specifications)

The parts are also identified on the score as printed or displayed.