Introduction, and question on symbol placement

[lilypond]

Wow, what great software.  I've been looking for something
like this, and am very glad to have found it.

I use lilypond to write lead sheets.  I have a chart with a
coda jump that occurs right after a second ending.  The coda
symbol gets placed quite high above the staff, high enough to
clear the second ending.

Is there a way I can tweak the placement of the Coda symbol
to bring it a little (or a lot) lower, and hopefully cause
the software to spread the horizontal spacing a little to
prevent crowding?  Even if it creates crowding, I'd like to 
learn how to tweak the 'altitude' of the Coda sign.

Thanks!

Jim


\version "2.14.2"

somechords = \chordmode {
  c4 a:m d:m g
} % somechords

amelody = \relative c' {
  c4 c c c
} % amelody

\score {
  <<
    \new ChordNames {

      \set chordChanges = ##t
      \repeat volta 2 \somechords
        \alternative { \somechords \somechords }
      \somechords
      \somechords
    }

    \new Staff { 

      \repeat volta 2 \amelody
        \alternative { \amelody \amelody }

% this Coda jump is 'way up in the air', can I bring it down
% closer to the staff somehow?
  \mark \markup { \musicglyph #"scripts.coda" }

      \amelody
      \amelody
    }
  >>
  \layout {}
} % score