Brother Marine!
I just restarted my CFists last week and had been playing around with color schemes myself. I found that using the Foundation Necron Abyss followed by a wash of Badab Black, then highlighted with Necron Abyss, Abyss+Regal, and a final highlight of Ultramarines Blue worked very nice to produce that incredibly dark blue.
For the fists and shoulder edges, I went with Blood Red followed by Badab Black, and then Blood Red again. I'm not certain if I'm going to highlight again, but I'd probably add a drop of Bleached Bone to get it lighter - the slight yellow in it keeps the red from getting pink. Chest eagle and other metal bits are in Boltgun, Badab again, Boltgun, then Chainmail.
I found
this blog that made some pretty decent Crimson Fists (check out the Sternguard, nice!) and has a step-by-step tutorial, albeit not a very comprehensive one. I'd rank it about as detailed as a White Dwarf painting tute.
Good Luck!