I use the 2 parts coconut oil : 1 part chocolate ratio, first because that is what Winencandy said, and she must be obeyed in all matters candy. Second, because it makes me feel I am getting a fat-centric treat that tastes like chocolate, and not a chocolate treat that just happens to have some fat in it. Once they harden up in the fridge they are fine, although they do start melting in your fingers. The fix for that: pop them into your mouth right away!
Phigment, I know of no substitute for the coconut oil. Unless you just made a beautiful ganache and roll it in cocoa powder. Do you do dairy?