Modal notation

[Victor Eijkhout]

I’m trying to notate 1200-ish School of Notre Dame modal notation, and the 
Gregorian notation works out reasonably well.

1. I’m not finding a symbol for a “plica”: single note with ascending or 
descending tail on both sides. Does that exist?

2. More seriously: if I don’t include a Lyrics line, all notes get smushed 
together. 

3. Also: sometimes I want to set a small snippet where the exact pitch is 
irrelevant, but removing the Clef_engraver doesn’t work:

Advise? Thanks,

Victor.

Here’s a snippet:

    \include "gregorian.ly"
%% #(ly:set-option 'crop #t)

voiceglobal = {  \omit Dots  \omit Tie  \time 3/4 }

  \score{
    <<
    \new VaticanaVoice = "voice" 
    \with { \remove "Clef_engraver" }
    \relative c' 
    {
      \voiceglobal
      \key c \major
      \clef "vaticana-do2"
      \[ a2 \pes b4 \flexa a2 \]
      \[ a4 \pes b2 \]
      \[ b4 \flexa g2 \]
    }
%%    \new Lyrics \lyricsto "voice" {   Vi    }
    >>
    \layout { #(layout-set-staff-size 36) }
}
\version "2.24.1"