Looking good!
In my minds eye, everything should be symmetrical but deep down I know that symmetry doesn't mean all that much when in space
What are the 'wings', engineering spaces on one side and fuel on the other? Could you have them layered on the 'spine' to make it thicker and have stubbier wings instead?
The wing on the starboard side is the missile launchers (10 racks in all - 2 side-by-side stacked 5 deep), plus 2 CIWS systems on the top and bottom and 3 missile magazines on the back.
The port side wing are the 6 lasers (not turreted), plus the 6 shield and 2 CIWS systems.
Using Google Sketchup, you can pretty much "snap" them together in any configuration, so going with a central spine and stacking is an option. Going completely vertical is option. The sky's the limit. Took me about 1 hour to snap it all together in the way I wanted. Once you figure out the basics of how to snap things together in Sketchup so that components line up properly, the rest is easy.