Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison
We don't do a ton of 4c process but what we have done on dark shirts looks good at least to me and customer are happy....just a base white and the process inks which are triple blend inks. My biggest problem at one time doing 4c process I didn't trust what I saw on screen and would increase the colors/brightness as my image would look washed out, but once I just went with the washed out look, the seps looked great and printed very nice, the other way the print got dark very quick causes us to stop and clean the screens or reburn higher mesh counts. My normal mesh is 230 and maybe 280's color and my white 180.