We often fabricate and install backsplashes.
A 4" backsplash is standard in bathrooms. However, tooler splashes are required for vanities with top-siting sink vessels or when the water valves are set on the wall. In kitchens, we install 4" backsplash only in spec houses. We advise customers against this option, as the cost is usually on par with the cost of tiles that will cover the whole splash area. Of course, you need to pay for the installation, but you are getting a full splash. The other option is to use the top stone material. This option would cost the most, but you get a great-looking, smooth, jointless, and easy-to-clean surface.