generating simple leadsheet with chords and empty staff

[Rob Torop]

I want to generate a lead sheet in which

• chord names are shown at the top
• below that is an empty staff
• if I repeat a chord, e.g.  with \repeat percent 2 { f1:7 },   then above the staff I'll see F7 following by a percent over the following bar.
• Each staff line contains exactly 4 bars
• First line is not indented
  

Below is my current attempt.  My questions are

• Is there a way to avoid needing to put the repeating 12 bars of silent rests in the melody - clearly it's not a good way to do it
• Can this be done more concisely?
  

\version "2.18.2"

chordmusic = \relative {
    \chordmode {
        \repeat percent 4 { f1:7 }                            \break
        \repeat percent 2 { bes1:7} \repeat percent 2 { f1:7} \break
        \repeat percent 2 { c1:7}   \repeat percent 2 { f1:7}
    }
}

melody = { \repeat unfold 12 {s1} }
%melody =  {}

\score {
  <<
    \new ChordNames { \chordmusic }
    \new Staff      { \melody     }
  >>

  \layout {
    indent = #0
    \context {
        \ChordNames
        \consists "Percent_repeat_engraver"
        \override PercentRepeat.extra-offset = #'(0 . 1)            
         
    }  
  }
}