We're considering Brazilian green slate in our new country home for several reasons-more rustic than the Halila limestone we chose for our current urban home, roughness allows us to use larger pieces for interior flooring as well as exterior lanai for an indoor-outdoor feel, also for showers for flush-no curb, floor-through feel in bathrooms, and because they seem more forgiving wrt cleaning in showers and outdoors. We have 2 design dilemma questions: 1) what types of cabinetry wood veneers and wall colors would you recommend that are low-contrast and 2) what would you recommend to waterproof the shower walls (continuing the slate up the walls could make the shower and bathroom too dark)?