Well, you're OCD, right?
Interesting how the lighting (and maybe natural variation in the #8 color?) seems to lend them each a slightly different tone, from 'black' on the left, all the way down to 'cordovan' on the right. Or maybe it's my monitor.

What are your thoughts on giving each it's own personalized 'shining' regimen with the thought of bringing about a slightly unique coloring i each pair over time? Like identical twins where one's hair turns slightly blonder in the summer.....