centering different time signatures

[Kieren MacMillan]

Hi all,

In the snippet included below, I’d like to have the two time signatures 
center-aligned, but haven’t found the correct incantation.
(Gould has nothing specific to say about this situation, but her polymetric 
time signatures *appear* to be centre-aligned, and not left-aligned like Lily’s 
default.)
Any help would be appreciated.

Thanks,
Kieren.
________________________

\version "2.19.18"

\layout {
  \context {
    \Score
    \remove "Timing_translator"
    \remove "Default_bar_line_engraver"
  }
  \context {
    \Staff
    \consists "Timing_translator"
    \consists "Default_bar_line_engraver"
  }
}

shortTSmusic = {
  \time 4/4 g'4
}

longTSmusic = {
  \time 12345/4 g'4
}

\score {
  <<
    \new Staff \shortTSmusic
    \new Staff \longTSmusic
  >>
}
_______________________

Kieren MacMillan, composer
www:  <http://www.kierenmacmillan.info>
email:  address@hidden