"z" rest placement

[Dan Eble]

Does anyone else think that the automatic placement of the second rest in this 
example is distractingly low in the “z” style?  (If you have enough experience 
to suggest a solution, please do.  I haven’t looked at the rest collision code 
yet.)  Thanks.
— 
Dan

\version "2.19.16"
\language "english"

% excerpt from the hymn tune "Diadem" by James Ellor
soprano = \relative {
  f''4 | ef4.( d8 c[ ef] | d4. c8 bf[ d] | c4. bf8 a[ c] | bf4) bf
}

alto = \relative {
  f'4 | g4 g r | f f r | f f r | f f
}

music = \relative {
  \key bf \major
  \time 3/4 \partial 4
  \partcombine \soprano \alto
}

\score {
  \new Staff { \music }
}

\score {
  \new Staff \with { \override Rest.style = #'z } { \music }
}