I would choose the lighter one, for other reasons stated, as well as the darker one may only carry one barring gene, which would make it impossible to sex his babies at birth, costing you $ and effort in raising the babies to crow/lay age. Go with the lighter one.
if the darker one DOES have two barring genes, he has bad barring for a roo, and for that reason he is voted off the island. No way to make a good answer out of his coloring. If he was my only roo I would not hesitate to use him. I have a dark barred olive egger roo that served me very well this year, but I am growing out his replacement as we speak. He is light, good barring, clean legged, bearded, all improvements on the dad. Dad has been a very good roo. I will miss him when his time comes, to be sure! I think I will put some effort into re-homing him rather than using the stew pot as the first recourse to solving the problem of the extra roo. May even keep him 'in reserve' just in case his son tips over for some reason, or gets predated.