Let me say at the outset that I suspect this may be impossible. I am thoroughly deadlocked at a page of the quartet of the composer I am setting. This section is in polymeter, but the composer has scaled the durations of the viola and cello by an unknown factor, and also and insists on the end of the staves not being at the some point. I am unable to see how to implement the page breaks in lilypond.
I can't provide a MWE because I simply cant get anything useful to work. Please refer to the attached image. The upper tow parts are supposed to be at tempo 52. and the lower at 63, but lilypond of course does not lay out by tempo.
The poymeter examples in the NR are great, but it's the end of system unevenness at the right hand side of the page I have no idea how to deal with.
Andrew
polymeter.png