We are installing Daltile Bright White 3x12 inch tile on the shower walls and a Carrara marble mosaic tile in herringbone pattern on the shower/bath floor. What grout colors would work best with this combination of tiles? I want the wall tile grout to be very subtle and floor tile grout to be very complimentary. I also want the grout to have some advantages in being as low maintenance as possible under the circumstances. Any help is much appreciated!