So, I'm using BIAB 2010.5, so I'm not sure if this will be exactly the same... but it's something like this:
File menu: Notation Window: Click Opt.: Chord Vert Pos. THAT number will adjust the height of your chords. I think the default is 5, but you can try a 1 in there. Then, hit ok, and hit print and view a preview of it to see if you like it.