I think slate looks really nice also on the website but have never seen it in person. I am following this thread as I select my configuration (there are limited options in my 31 size two-tone, as I like cooler colors and most are so warm-toned when I saw them in person).
OP, would you consider a color in the middle as an option? When I was searching for photos of slate, the two-tone 36 with a slate dial is what kept popping up and it looks gorgeous. Unfortunately, it looks like it is not an option in your 36 with diamond markers, but do you have any interest in the other colors?
Of these two options, I think the black is more chic and the MOP is prettier and probably more versatile.