Since you are painting for Empire for
WHFB, any idea what you are looking to accomplish? It may be worthwhile to take a look at the Uniforms and Heraldry book that is available.
http://www.games-workshop.com/gws/catalog/productDetail.jsp?catId=cat440089a&prodId=prod2120005
There are lots of textures, materials and colors in the Empire, my suggestion is to start with two colors that you think look good together for the primary troops like the State Troops or Handgunner. You can also get away with lots of different choices for different types of units.
If you are trying to replicate the two color quadrant scheme, grab a color spray that will compliment your red (if you intend to use red still) like yellow. Carefully brush in your border lines between colors before finishing painting the quadrant. I personally like to shade and highlight two levels in either direction but Army painter quickshade appears to do good work too!
http://www.thearmypainter.com/gallery_presentation.php?GalleryId=36&Gallery=Renaissance Mercenaries&page=1