Solved overlaying a 2nd voice with cross-staff stems....
\version "2.18.0"
upperOne = \relative c {
r8
\change Staff = "lower"
\stemUp
\set tieWaitForNote = ##t
\tuplet 3/2 {
e16~ g~
\change Staff = "upper"
c
}
\change Staff = "lower"
\stemUp
\crossStaff {
<e, g >4
}
}
upperTwo = \relative c' {
s8 \stemUp
\override TupletNumber.transparent = ##t
\override NoteColumn #'ignore-collision = ##t
\set
tieWaitForNote = ##t
\once \override Stem.transparent = ##t
\override Flag.transparent = ##t
\tuplet 3/2 { s8 c16~ }
<c e>4
}
lower = \relative c, {
\time 2/8
\clef bass
\set tieWaitForNote = ##t
\stemDown
\tuplet 3/2 { c16_~ g'~ c_~ } s8
< c, g' c >4
}
\score {
\new PianoStaff <<
\new Staff = "upper" <<{ \upperOne } \\ { \upperTwo }>>
\new Staff = "lower" \lower
>>
\layout {
\context {
\PianoStaff
\consists #Span_stem_engraver
}
}
}