Shifting notes horizontally

[Jim Long]

I know this subject has come up before, but I can't seem to find
the right search string to yield an answer that works for me.

The attached example shows a note from a CueVoice context that
overlaps a rest in a normal voice context.  By default, Lily
engraves the normal rest lower than normal to avoid colliding
with the CueVoice, but otherwise keeps the cut note and the rest
aligned vertically, because they occur at the same musical
moment.  Very logical.

I'm experimenting with other placements of the rest, such as
using a pitched rest to move rest vertically lower or higher.
That works a treat.

I'd also like to try adjusting the rest horizontally to the right
to distance it from the cue note.  This may or may not look good
aesthetically, or make sense to the performer, but I would at
least like to learn how to do it, and then judge the clarity of
the resulting engraving.

But I can't find a way to make the 'r4.' move to the right, so
that it doesn't appear directly beneath the cue note.

Is there a way to insert empty horizontal staff space at an
arbitrary point in a particular voice?  Yes, much like \hspace in
markup.

Thank you!

\version "2.16.1"

melody = \relative c'' {
  <<
    \new CueVoice { c4. }
    {
%    \once \override NoteColumn #'force-hshift = #20
%    \once \override Rest #'X-extent = #'(-2.5 . 25)
%    c,4.\rest
    r4.
    }
  >>
  \relative c' { c8 d e  c d e   c d e }
} % melody


\score {
  \new Staff {
    \time 12/8
    \melody
  } % Staff
} % score