clefs and positioning

[Timothy C Litwiller]

I am try to set a piece that a friend wrote recently
it is what we call a Mens Quartet vocal piece.

The top line of notes above the words is almost right if I use \clef 
neomensural-c4 or c3  c4 is on the line above the space where we need it 
and c3 is on the line below where we need it.

what ever changes we do should also affect the pitch of the song

I've been playing with the different thing in the clef section of the 
manual but don't understand what I am doing yet.