I'm not entirely convinced of making this responsive, in the particular area of Jazz leadsheets. I've found myself preferring line breaks at regular intervals (mostly every 4 bars, with exceptions for pickups and alternate endings), rather than trying to cram as many bars as possible onto each line.
The beauty of the system is that a flex box rule of flex: 1 1 25%; will give you 4 bars per line (each averaging 25% of the width). The system is flexible.
I'm not entirely convinced of making this responsive, in the particular area of Jazz leadsheets. I've found myself preferring line breaks at regular intervals (mostly every 4 bars, with exceptions for pickups and alternate endings), rather than trying to cram as many bars as possible onto each line.