Said i say something more on this awhile ago. Sadly my camera is bit awful and so Its a bit limited, hopefully you can make out something in the Gloom!
Essentially Ive found the best two shades are Thraka Green and Leviathan Purple
Seth's wearing the Green and the Tactical Marine the Purple. The Green makes a great base for a dark red, such as the Flesh Tearers Colour scheme. The Purple a base for a lighter red. Its what I use for most of my blood angels. Baal Red is a great colour to blend tones if youve gone a bit overboard with layering. Gryphonne Sepia is great for adding shades later in spots that were missed or got accidentally painted over. All in all buy the whole new wash set theyre great and all have a use! Hope this helps, what washes do you use for your chaps?