Guy who put the /co/ chart together here.
The main complaint is that the labels don't match the characters, either in terms of description or ethnicity. Or it could be more character-specific, which I think I'd like, as it would represent our characters better.
At the time I threw it together, I just kind of made it an increasing gradient.
Also, I mainly just selected characters I liked. Anyone feel free to make your own or replace any of the entries if you feel it would make a more definitive /co/ version.