12/8 upper and 4/4 lower staves with equal bar duration

[Javier Ruiz-Alma]

I'm trying to typeset a piece marked with 12/8 upper and 4/4 lower staves.  By default, Lilypond forces both staves to 4/4.  I tried the code below, which allowed independent staff timing, but the bars are now decoupled.

Any ideas on how to mod this to get bars on both staves synched up to same duration?

Javier

 

\version "2.14.2"
rightHand= \relative c''{
 \time 12/8
 \clef treble
  \repeat unfold 12 {d8 c8}
}
leftHand=\relative c{
 \time 4/4
 \clef bass
    \repeat unfold 6 {d4 c4}
}
\score{
    \new PianoStaff <<
       \new Staff \with {\consists "Bar_number_engraver"
       } \rightHand
       \new Staff \with {\consists "Bar_number_engraver"
       } \leftHand
    >>
    \layout{
         \context {
        \Score
        \remove "Timing_translator"
        \remove "Default_bar_line_engraver"
        \remove "Bar_number_engraver"
        \override SpacingSpanner #'uniform-stretching = ##t
        \override SpacingSpanner #'strict-note-spacing = ##t
        proportionalNotationDuration = #(ly:make-moment 1 64)
      }
      \context {
        \Staff
        \consists "Timing_translator"
        \consists "Default_bar_line_engraver"
      }
      \context {
        \Voice
        \remove "Forbid_line_break_engraver"
        tupletFullLength = ##t
      }
    }
  }