I want to *force* spacing

[Fredrik Carlén]

Hi! I want to make a sheet that has the approximate look of the (among dummers)
classic "Stick Control" by G.L. Stone.
This book has you practising combinations of right hand strokes and left hand
strokes, like so: RLRR LRLL. My problem is that if I just write out the row of
combinations and notes without any whitespace, it's quite unreadable.
I need to separate the combinations so it's possible to see what's going on,
with some kind of spacer/whitespace thingy. Someone suggested \skip or s, but
these take up space so they disturb the division of the note rows into bars, for
instance:
(without \skip) | RLRRLRLL | (with skip) |RLRR LRL|L . SkipMusic and SkipEvent
are fillers that "take up duration" as per the page
http://lilypond.org/doc/v2.9/Documentation/user/lilypond-internals/SkipMusic#SkipMusic
. I suppose I'd like a filler that does *not* take up duration. I cannot find
such a filler, but surely there must be one? At least there *should* be one,
otherwise I have to use something other than Lilypond for my upcoming drummer's
resource website.

/Fredrik