petrucci style notehead for MetronomeMark, plus Piae Cantiones style G clef and time signature

[Jeff Olson]

This is my first time using quasi-mensural notation for modern notation 
readers (going for medieval look, not historical accuracy).

If you haven't gagged at that, I'd like some help on a few items.
Here's how the original starts ... (IMSLP260656 p48)

InDulciJubilo1910

And this is my approximation so far (using more familiar note durations) ...

MWE-mensural.png

My MWE-mensural.ly so far ... (constrained to overrides in my Voice 
variable vs new MensuralStaff)

\version "2.24.0"
vexDUMa = \transpose c c' {
  \tempo 2=100
  \time 6/8
  \override Staff.TimeSignature.style = #'mensural
  \clef "petrucci-g"
  \override NoteHead.style = #'petrucci
  \override Staff.MetronomeMark.style = #'petrucci
  \override Staff.AmbitusNoteHead.style = #'petrucci
  \cadenzaOn
  c4\(  c2 c4 e2 f4   g2 a4 g2\) \bar "," %1
  g4\(  c2 c4 e2 f4   g2 a4 g2.\) \breathe \bar "," %2
  \bar "||"
}
\score {
  { \vexDUMa }
  \layout { \context { \Staff \consists "Ambitus_engraver" }}
}

My questions ...

1)  How to get petrucci style note head in the tempo indication?

2)  Where to get the G clef as used in Piae Cantiones?

3)  How to get the time signature as used in Piae Cantiones?

TIA,
Jeff


\version "2.24.0"
vexDUMa = \transpose c c' {
  \tempo 2=100
  \time 6/8
  \override Staff.TimeSignature.style = #'mensural
  \clef "petrucci-g"
  \override NoteHead.style = #'petrucci
  \override Staff.MetronomeMark.style = #'petrucci
  \override Staff.AmbitusNoteHead.style = #'petrucci
  \cadenzaOn
  c4\(  c2 c4 e2 f4   g2 a4 g2\) \bar "," %1
  g4\(  c2 c4 e2 f4   g2 a4 g2.\) \breathe \bar "," %2
  \bar "||"
}
\score { 
  { \vexDUMa }
  \layout { \context { \Staff \consists "Ambitus_engraver" }}
}