Please help with fretboard diagram spacing

[Tom Swan]

I didn't get any response to my request for advice on adjusting spacing between
a fretboard diagram and the associated staff. Does anybody have any suggestions?
I am stuck and need help with this. Thanks! Here is the snippet -- I would like
more space below the fretboard diagram and the staff, but I've tried every
override and \paper setting I would find with no results.

\version "2.18.2"
<<
 \new Staff {
   \new Voice = “scale” \relative c {
     <f-1\6>4^\markup {
     \override #'(size . 4.0) {
       \override #'(fret-diagram-details . (
         (orientation . #'landscape )
         (finger-code . #'in-dot )
         (dot-color . #'black)
         (dot-radius . 0.35)
         (dot-position . 0.5)
         (top-fret-thickness . 7)
         (fret-count . 7)) )
       \fret-diagram-verbose #'(
         (place-fret 6 1 1 inverted)
         (place-fret 6 3 2)
         (place-fret 6 5 4)
       ) 
     }
   } 
     <g-2> <a-4> <b-1\5> | 
   }
 }
>>

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