Shorten stem length

[Carolyn Beeton]

I am trying to shorten the stem length for a couple of notes (because there is 
another voice underneath, from the other staff) to reproduce this music.



This snippet shows the default rendering, and then I’m trying to shorten and 
revert the stem length, but nothing changes.  This is only the one voice, but I 
can’t shorten the stems even in this simple example.


I have been able to make the stems long, but not short.
What am I doing wrong, and how can I achieve this?

Thanks,
Carolyn



\version "2.24"
\include "english.ly"


shortBeams = {   % none of this works
  \override Stem.details.beamed-lengths = #'(0.5)
  \override Stem.details.beamed-minimum-free-lengths = #'(0.5)
  \override Stem.details.beamed-exteme-minimum-free-lengths = #'(0.6)
  \override Stem.details.stem-shorten = #'(0.5)
}

\relative c'
{
  \time 6/8
  e'4^"default" d8 cs4 d8 | d b cs d e8 e8 | d4 c8 b4 c8 ~ | 8 a b ~ 8 d c 
  \section
  e4 d8 cs4 \shortBeams d8^"short" | d b cs \revert Stem.details.beamed-lengths 
d^"revert" e8 e8 | 
  d4 c8 b4 c8 ~ | \shortBeams 8^"short" a b ~ \revert 
Stem.details.beamed-lengths 8 d c 
}