Main problem I see with the roo is the eye, not sure on the availabilty of blacks over there? maybe limited, but the eye should be a nice black & show no fuzzyness in the pupil shape, shame.
splash is just two copies of the blue gene, blue dilutes black, so 1 copy turns a black blue, 2 copies dilute the black twice into splash.
Over here splash birds tend to be stock birds, you get a better size & strength, so if you have a small black, put it to a large splash, & get good sized blues.
never breed blacks from blue crossing, else you get red leakage in your neck. Keep blacks with blacks, and blues with blue/splash & blue blacks. ( sorry should be clearer )
I mean dont breed a pure black with a blue black, else your line will carry blue ( hidden ) and will mess up things when you need a pure black.