distance between staves?

[Marc Hohl]

I have a file with normal and tab staves, and in the last bar
the highest notes touch the tab staff regardless of the
values for VerticalAxisGroup #'minimum-Y-extent.
How can I increase this distance?

Thanks in advance!

Marc

\version "2.13.6"
\include "deutsch.ly"

#(set-global-staff-size 17)

\header {
  title = "distance test"
  composer = "unknown"
}

\paper {
  indent = 0
  ragged-right = ##f
  between-system-space = 2\cm
  between-system-padding = #5
}

\layout {
  \context {
    \Staff
    \override VerticalAxisGroup #'minimum-Y-extent = #'(-10 . 10)
  }
}

global = {
  \time 4/4
  \key c \minor
}


GuitarLastVerse = \relative c' {
  \repeat unfold 16 g16\5
  \repeat unfold 16 g16\5
  \repeat unfold 16 f16\5
  \repeat unfold 16 f16\5
  \repeat unfold 16 a16\4
  \repeat unfold 16 b16\4
  \repeat unfold 16 d16\3
  \repeat unfold 8 b'16\1
    \repeat unfold 8 h16\1
}

BassLastVerse = \relative c {
  \repeat unfold 16 c16\2
  \repeat unfold 16 c16\2
  \repeat unfold 16 b16\2
  \repeat unfold 16 b16\2
  \repeat unfold 16 d16\2
  \repeat unfold 16 es16\2
  \repeat unfold 16 g,16\3
  \repeat unfold 4 g'16\1
    \repeat unfold 4 f16\1
    \repeat unfold 4 es16\2
    \repeat unfold 4 d16\2
}

\score {
  <<
    \new StaffGroup = "Guitar" <<
      \new Voice {
        \clef "treble_8"
        \global
        \override Voice.StringNumber #'transparent = ##t
        \GuitarLastVerse
        \bar "|."
      }
      \new TabVoice {
        \clef "moderntab"
        \global
        \set TabStaff.stringTunings = #guitar-tuning
        \GuitarLastVerse
      }
    >>
    \new StaffGroup = "Bass" <<
      \new Voice {
        \clef "bass_8"
        \global
        \BassLastVerse
      }
      \new TabVoice {
        \clef "moderntab"
        \global
        \set TabStaff.stringTunings = #bass-tuning
        \BassLastVerse
      }
    >>
  >>
  \header {
    piece = "Last Verse"
  }
}