\version "2.19.55"
 
 #(define (my-proc grob)
    (let ((default-stil (ly:ottava-bracket::print grob))
          (lb (ly:spanner-bound grob LEFT)))
      (if (eq? lb (ly:spanner-bound grob RIGHT))
          (let* ((txt (ly:grob-property grob 'text))
                 (txt-stil (grob-interpret-markup grob txt))
                 (txt-stil (ly:stencil-aligned-to txt-stil X CENTER))
                 (lb-center (interval-center (ly:grob-extent lb lb X))))
            (ly:stencil-translate-axis txt-stil lb-center X))
          default-stil)))
 
 #(define (my-proc2 grob)
    (let* ((ncs (ly:grob-object grob 'side-support-elements))
           (ncs (ly:grob-array->list ncs)))
      (if (> (length ncs) 1)
          ;; Return default stencil
          (ly:ottava-bracket::print grob)
          (let* ((txt (ly:grob-property grob 'text))
                 (txt-stil (grob-interpret-markup grob txt))
                 (txt-stil (ly:stencil-aligned-to txt-stil X CENTER))
                 (txt-stil (ly:stencil-aligned-to txt-stil Y CENTER))
                 (bound (car ncs))
                 (lb (ly:spanner-bound grob LEFT))
                 (sys (ly:grob-system grob))
                 (lb-coord (ly:grob-relative-coordinate lb sys X))
                 (bound-center (interval-center (ly:grob-extent bound sys X))))
            (ly:stencil-translate-axis txt-stil (- bound-center lb-coord) X)))))
 {
   \override Staff.OttavaBracket.no-bracket-for-singleton = ##t
   \ottava #1 c'''1
   \ottava #2 c''''1
   \ottava #-1 c''1
   \ottava #-2 c'1
   \ottava #1 <c''' d''' e''' f'''>1
   \ottava #2 <c'''' d'''' e'''' f''''>1
   \ottava #-1 <c'' d'' e'' f''>1
   \ottava #-2 <c' d' e' f'>1
   \ottava #1 <cis''' dis''' eis''' fis'''>1
   \ottava #2 <cis'''' dis'''' eis'''' fis''''>1
   \ottava #-1 <cis'' dis'' eis'' fis''>1
   \ottava #-2 <cis' dis' eis' fis'>1
   \time 3/4
   \ottava #1 c'''2.
   \ottava #2 c''''2.
   \ottava #-1 c''2.
   \ottava #-2 c'2.
   \ottava #1 <c''' d''' e''' f'''>2.
   \ottava #2 <c'''' d'''' e'''' f''''>2.
   \ottava #-1 <c'' d'' e'' f''>2.
   \ottava #-2 <c' d' e' f'>2.
   \ottava #1 <cis''' dis''' eis''' fis'''>2.
   \ottava #2 <cis'''' dis'''' eis'''' fis''''>2.
   \ottava #-1 <cis'' dis'' eis'' fis''>2.
   \ottava #-2 <cis' dis' eis' fis'>2.
   \time 4/4
   \ottava #1 c'''2 d'''
   \ottava #2 c''''2 d''''
   \ottava #-1 c''2 d''
   \ottava #-2 c'2 d'
 
   \ottava #1 c'''1 \break
   c'''1
   \ottava #2 c''''2 d'''' \break
   c''''1
   \ottava #1 c'''1 \break
   c'''2 d'''
   
   \ottava #2 c''''1 \break
   c''''2 d'''' \break
   c''''1 \break
   c''''1
 }