The only thing consistant about breeding for color in nigerians is that nothing is consistant.
You can breed for eye color - blue eye color is dominant in, but that doesn't always mean that you get it. If two blue eyed parents are bred, but they have the recessive brown gene, you only have a 50/50 shot at blue eyed kids. I have read that moonspots are a dominant trait, as is belting, frosting and white polls. I have moonspotted does in my herd, and they have thrown babies with and without moonspots.
I have a red and white , blue eyed buck that I bred to a mostly white, spotted, brown eyed doe...first breeding produced a black baby with white spashes/brown eyes, and the next breeding produced two red and white babies with blue eyes. I bred the same buck to a chamoisee doe - first breeding produced a cream and white baby, and red and white baby, and the second breeding produced a black and white baby...all with brown eyes.
I have a chocolate, buckskin buck with brown eyes that I bred to 3 does - one brown eyed red doe, one blue eyed red doe, and one black with moonspots and brown eyes.
The results...
buck x doe 1 - 1 brown, 1 tricolor, 1 light caramel color - all brown eyes. Buck x doe 2 - 1 brown, 1 cream, 1 red/white with blue eyes.
Buck x doe 3 - 1 blk/wh, 1 blk/wh with moonspots, 1 white/blk, 1 chocolate.
There is a really good website for genetic info -
http://members.cox.net/foxcroft/genetics.htm but I agree with the above post - breed for udder, conformation and health. Colors, patterns, and 'flash' are just the icing on the cake!
By the way - I just saw that you are considering Goodwood Weisbaden as a sire...I have a grandson and 2 grandaughters of his (all sired by his son - Lost Valley Omega Red) and the girl's udders are fantastic. Don't know about the other sire option, but I'd go with Weisbaden.