Problem spacing arpeggio

[Nick Payne]

In the attached example, in the first bar I can increase the spacing 
between the first chord and the the arpeggio on the second chord by 
overriding Staff.Arpeggio #'X-extent, but in the second bar, using the 
same override does nothing to increase the spacing between the arpeggio 
and the preceding note. What means can I use to increase the spacing there?

Nick


\version "2.13.3"

#(ly:set-option 'delete-intermediate-files #t)

\pointAndClickOn

arpspace = \once \override Staff.Arpeggio #'X-extent = #'(-2 . 1)
ignct = \once \override NoteColumn #'ignore-collision = ##t

treble = \relative c' {
        a4 \arpspace cis\arpeggio
        f,32 d a'' d,, f d a'' d,, \arpspace f\arpeggio d a'' d,, f d a'' d,,
}

bass = \relative c {
        <e a,>4 <a e a,>\arpeggio
        s \ignct d,,\arpeggio
}

middle = \relative c {
        s2
        f8 f \ignct f f
}

\score {
        <<
                \context Staff = guitar {
                        \set Staff.connectArpeggios = ##t
                        \clef "treble_8"
                        \key d \minor
                        \time 2/4
                        <<
                                \context Voice = "1" { \voiceOne \treble }
                                \context Voice = "4" { \voiceFour \bass }
                                \context Voice = "2" { \voiceTwo \middle }
                        >>
                }
        >>
        \layout {
                \context {
                        \Staff 
                                \consists "Span_arpeggio_engraver"
                }
        }
}