Rests vertical position problem

[Jacques Menu]

Hello folks,

In the attached example, the \voiceOne and \voiceTwo commands used for the 
first score lead to the eigth rests in measure 2 to appear too high.

Removing them as in the second score makes the look more satisfying in this 
regard, but then measure 1 gets awful.

Is there a way to use some equivalent of \voiceOne and \voiceTwo measure-wise 
in such a case, using it only in measures that have more than one voice playing?

Thanks for your help!

JM

RestsVerticalPositionProblemSubmittedToList.ly
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