As I lived in Perth at the moment, here in Australia and we usually used the racks that are 3 bottles deep. In addition to the back lit onyx. We set it back 100mm from the rear, top using a broom or brush to give it a bit of texture but primarily to water proof the wall as we were underground, then we painted it with a matt black, storage bottles of wines I don’t drink but could find other uses for this space. Narrow, the house-owner wisely decided to store the wine bottles. Look the gorgerous picture, Wow!