lilypond-book lyrics vs staff vertical spacing

Question

I want to add more vertical space between the lyrics and the line of staff above and below. I have been able to lower the lyrics from the staff above by overriding the nonstaff-relatedstaff-spacing.padding, however I can't seem to create more space with the staff below. The answers in Lilypond spacing between lyrics and next system and Increase space between lines of a staff in LilyPond would be very applicable, however with lilypond-book any changes I make in \paper don't seem to appear in the resulting pdf.

example.lytex:

\documentclass[a4paper]{article}

\begin{document}

\section{A demonstration of the spacing problem}

\begin{lilypond}
\score {
  <<
    \new Staff {
      \new Voice = "music" {
        \override Score.BarNumber.break-visibility = ##(#f #f #f)
        b1 c' c' c'
        b c' c' c'
        b c' c' c'
        b c' c' c'
        b c' c' c'
        b c' c' c'
        b c'
      }
    }
    \new Lyrics \with {
      \override VerticalAxisGroup.
      nonstaff-relatedstaff-spacing.padding = #4
    }
    \lyricsto "music" {
      z y
      x w v u
      t s r q
      p o n m
      l k j i
      h g f e
      d c b
      \markup { \draw-line #'(3 . 0) }
    }
  >>
}

\layout {
  indent = 0\cm
}
\end{lilypond}

More vertical space between the lyrics and the staff below is desired.

\end{document}

Additional information: Lilypond version: 2.22.0, pdfTeX 3.141592653-2.6-1.40.22 (TeX Live 2021/Cygwin)

Answer 1

Changes made in \paper not appearing in the resulting lilypond-book output seems to be in line with a known issue/warning in the documentation https://lilypond.org/doc/v2.20/Documentation/usage/invoking-lilypond_002dbook .

A solution and deeper explanation can be found in this thread: http://lilypond.1069038.n5.nabble.com/system-system-spacing-in-lilypond-book-file-td10128.html . In short, adding \newcommand{\betweenLilyPondSystem}[1]{\vspace{1mm}\linebreak} to the LaTeX preamble (adjusting \vspace as desired) can be used to increase the amount of vertical space between systems.

Using the example above:

\documentclass[a4paper]{article}

% http://lilypond.1069038.n5.nabble.com/system-system-spacing-in-lilypond-book-file-td10128.html
\newcommand{\betweenLilyPondSystem}[1]{\vspace{55mm}\linebreak}

\begin{document}

\section{A demonstration of the spacing solution}

\begin{lilypond}

\score {
  <<
    \new Staff {
      \new Voice = "music" {
        \override Score.BarNumber.break-visibility = ##(#f #f #f)
        b1 c' c' c'
        b c' c' c'
        b c' c' c'
        b c' c' c'
        b c' c' c'
        b c' c' c'
        b c'
      }
    }
    \new Lyrics \with {
      \override VerticalAxisGroup.
      nonstaff-relatedstaff-spacing.padding = #4
    }
    \lyricsto "music" {
      z y
      x w v u
      t s r q
      p o n m
      l k j i
      h g f e
      d c b
      \markup { \draw-line #'(3 . 0) }
    }
  >>
}

\layout {
  indent = 0\cm
}
\end{lilypond}

More vertical space between the lyrics and the staff below is obtained.

\end{document}