Don always suggests using a male of the color that you are trying to achieve, such as trying to make Blue Coppers and getting nice blue coloring a person would use a Splash Copper male over a Black Copper hen.
I get my dark dark blues by using an extremely dark Blue Copper rooster who appears to be black, I have crossed this dark rooster and another one that I had over Blue Copper and Splash Copper hens and the results have given me very dark blue birds. However, I have a whole nuther battle one my hands because when I use these dark males I am perpetuating melanised birds to the extent that they do not show copper even though they are coppers. I am trying to find a happy medium but first and foremost in my program, I go for type and egg color.....the rest of it I will work on correcting later after I have established type and if I get good color in the copper while I am at it, I consider it a bonus.
Hope others will come by and give you their opinions and advise.