polymeter line breaks

[Adrian]

hi,

I'm trying to notate a score which contains multiple vocal parts, in 
which some of the parts have rhythmic 'phasing'- i.e. one or more extra 
notes are occasionally inserted to shift the part rhythmically with 
respect to the other parts.

The way I've been trying to do it is by treating it as a polymetric 
score, with occasional short bars inserted to represent the phasing.

It's great that Lilypond allows polymetric scores like this. However, 
I've struck a problem with line breaks. The attached example is a 
simplified illustration of the problem.

Here there are just two parts, and a 2/8 bar is inserted for the phasing 
at bar 3 of the upper part. After that there is no more phasing, so the 
subsequent 5/4 bars just continue with a rhythmic shift between them.

Lilypond seems to have trouble deciding where to put a line break, and 
the second line (after the phasing) continues off the page. I was hoping 
it would break one of the parts mid-bar to allow a sensible line break 
for both parts.

I'm using a slightly older version of Lilypond (2.18.2) so I don't know 
if the behaviour is any different in later versions.

Is there a way to allow it to break this line either automatically or 
manually? I tried inserting manual breaks, but it said: "warning: forced 
break was overridden by some other event, should you be using bar 
checks?" (which is odd, since I am already using bar checks).

Or perhaps there's a different way of notating the phasing that avoids 
the problem (while still giving a faithful visual representation of the 
phasing process)?

Thanks, Adrian

vocal.ly
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