\version "2.18.2"

H = \once \override Staff.NoteHead.style = #'harmonic-black
voiceFive = #(context-spec-music (make-voice-props-set 4) 'Voice)
voiceSix = #(context-spec-music (make-voice-props-set 5) 'Voice)

voiceone = \relative c'' {
  \voiceOne
  \clef "G_8"
  \time 4/4
  \key g \major
  b4 b2 r4 |
  b4 b4 r r |
  b4 b b b |
  b4 b b\harmonic b |
  b4 b \H b b |
}

voicetwo = \relative c {
  c1 | c1 | c1 | c1 | c1
}

noShift = \once\override NoteColumn.force-hshift = 0
voicethree = \relative c' {
  % save typing with \repeat …
  \repeat unfold 5 { s4 \noShift g4^~ g2 | }
}

voicefour = \relative c' {
  \voiceFour
  g4\rest g4 fis2 |
  g4\rest g4
  % no more force-shifting needed
  %\once \override NoteColumn.force-hshift = #2.0      % to prove it works here
  fis2 |
  g4\rest g4
  %\once \override NoteColumn.force-hshift = #2.0       %  doesn't work here
  fis2 |
  g4\rest g4 fis2 |
  g4\rest g4 fis2 |
}

voicefive = \relative c {
  % use 5 to make stems go up, 6 to make them go down
  %\voiceFive
  \voiceSix
  \set harmonicDots = ##t
  e'8\rest d2..\harmonic |
  e8\rest d2..\harmonic |
  e8\rest d2..\harmonic |
  e8\rest d2..\harmonic |
  e8\rest d2..\harmonic |
}

guitar = << \voiceone \\ \voicetwo \\ \voicethree \\ \voicefour \\ \voicefive >>

#(set-global-staff-size 19)

\score {
  \new Staff \guitar
}