Issue with AikenHeads with overlapping parts

[Darren]

> I'm not top posting.

I'm trying to create a score for four voices SATB that uses AikenHeads (shaped 
notes).  When two parts on the same staff overlap on the same notes (for 
example soprano and alto), it is customary to show the stems for the two parts 
going different directions so each part realizes that it is to sing the 
overlapping notes.

When I try to do this with LilyPond 2.14.2, 

1. The heads face in opposite directions, which obscures the shape of the head.

2. I tried suppressing the Note Head for one of the parts (made it 
transparent), however the stem does not meet the note head of the opposite part.

Example .ly code follows.  It requires a bit of detail to demonstrate the 
problem.  I have a screen shot I can provide if that would help (but this 
interface doesn't accept attachments).

The bass staff demonstrates #1, the treble staff demonstrates #2.

Thanks for any assistance


\version "2.14.2"

global = {
  \key a \major
  \time 4/4
  \partial 4
  \aikenHeads
}

ignoreCollide = \override NoteColumn #'ignore-collision = ##t

sopranoNotesVerseOne =  \relative c' {
  \global \stemUp
  cis8 d e e e e e4. fis8 fis e8 ~ e2
}

altoNotesVerseOne = \relative c' {
  \global
  \new Voice {
    \override NoteHead #'transparent = ##t
    \ignoreCollide \aikenHeads \stemDown
    cis8 d
  }
  cis cis cis cis cis4. d8 d cis8 ~ cis2
}

bassNotesVerseOne = \relative c {
  \global \stemDown
  cis8 d a a a a a4. a8 a a ~ a2
}

tenorNotesVerseOne = \relative c' {
  \global
  \new Voice {
    \ignoreCollide \aikenHeads \stemUp
    cis,8 d
  }
  a'8 a a a a4. a8 a a ~ a2
}

trebleClef = \new Staff  <<
  \context Voice <<
    \sopranoNotesVerseOne
    \altoNotesVerseOne
  >>
>>

bassClef = \new Staff <<
  \clef bass
  \context Voice <<
    \bassNotesVerseOne
    \tenorNotesVerseOne
  >>
>>

\score {
  << \trebleClef  \bassClef       >>
  \layout { }
}