I've seen cognac colors (i think it was ostrich and maybe barenia?) that aged darker very elegantly. If I understand you HH, you are asking about color and patina? The lighter browns/tans would obtain darker patina from use. I think the whites, taupes, pinks - (cyclamen, fuchsia) - might possibly go a little grayer. I can't be absolutely sure but the lighter colors don't have the same saturation in leathers as the dark colors. Just my impression. Box would get shinier and deeper over time from consistent use.