trouble changing notehead size on percussion staff

[Niki Pantelias]

 Hello,

  The .ly file pasted in below demonstrates a problem I'm having with 
changing notehead sizes in a drum part.  When I run it as shown, the 
changes to font-relative-size have no effect, which seems to me to be 
a bug.

  If I comment out the line
  \apply #(drums->paper 'drums)
 the notehead size _does_ change, although of course the result looks 
nothing like a drum part :-)

  thanks,
  -- Niki

------------
\include "english.ly"

papersize = "letter"
\include "paper20.ly"

\include "drumpitch-init.ly"
Scale =
  \context Voice
  \notes
  {
    \time 4/4
    bd4 tomfl
    \property Voice.NoteHead \override #'font-relative-size = #-3
    tomfh tomml | tommh
    \property Voice.NoteHead \revert #'font-relative-size
    sn hh cymr |
    \bar"|."
  }

\include "english.ly"

\score {
  \apply #(drums->paper 'drums)
  \new Staff {
    \clef percussion
    \Scale
     }
 \paper { papersize = "letter"
          linewidth = \hsize - 0.9 \in }
 }