The natural walnut sounds amazing. That's probably going to be fantastic.

Did you do one of those visualization software things to see how the colors & patterns look together? The floor will be a big part.

I had to look up the Silestone El Statuario. The description is: 'A bluey white surface with light and bright veins in grey and pink hues.' I wonder if it might be more classic to use a natural stone instead of a manmade product that is trying to sort of look like a natural stone, since the manmade pattern might be subject to trend changes in the way it is approximating nature.....

I saw the other day here on Houzz that someone planned to make their counters of quartzite, a natural stone (not to be confused with quartz counters), which is largely white without all the troubles that marble would have in a kitchen.

Anyway, back t what you asked: I think the matte finish would be more livable for the backsplash.