>> In other words, we can't get the real width of the PDFs easily
>> within the texinfo framework. A variant of `@columnfractions` that
>> accepts both fractions and sample strings would be thus ideal.
>
> What prevents `lilypond-book` from determining the widths and
> inserting them? Perhaps with a @lilypond-width placeholder in the
> initial source?
Assuming a LilyPond snippet
@lilypond
c4
@end lilypond
you mean something like
@multitable {@lilypond-width
c4
@end lilypond-width} {foo} ...
...
? I don't think this flies. First of all, the arguments of
`@multitable` have to be strictly on a single line that must not be
broken; this makes such code very fragile. Second, how shall a
snippet width be specified for non-TeX modes?
Werner