Making some notes smaller and colored grey

[Paul]

Hi all,

I came up with the following code to color certain notes grey and make 
them smaller, to mark them as optional.  (It's for playing fast fiddle 
tunes on trumpet, where I have to strategically drop notes to keep up.)

I thought about submitting it to the LSR, but it uses 2.19.x 
functionality like \etc .  So I thought I'd post it here for now. 
Anything I'm missing that would improve it?

Cheers,
-Paul


\version "2.19.63"

makeGrey =
#(define-scheme-function
  (n) (number?)
  (rgb-color n n n))

makeNoteModifier =
#(define-music-function
  (size color music) (number? color? ly:music?)
  #{
    \override NoteHead.color = #color
    \override Stem.color = #color
    \override Flag.color = #color
    \override Dots.color = #color
    \override Accidental.color = #color
    \override NoteHead.font-size = #size
    \override Accidental.font-size = #size
    #music
    \revert NoteHead.color
    \revert Stem.color
    \revert Flag.color
    \revert Dots.color
    \revert Accidental.color
    \revert NoteHead.font-size
    \revert Accidental.font-size
  #})

opt = \makeNoteModifier -2 \makeGrey 0.75 \etc

blueNote = \makeNoteModifier 0 #blue \etc

\fixed c' {
  c8 \opt d e \opt fis
  g \opt { a bes c }
  c4. \opt c4. c4
  \blueNote c16 r c16 r r2.
}