We are building a new home, and at the point where we have to finalize our shower configuration to get the plumbing finished. We are very experienced do it yourselfers, but the one thing we cant find an answer for is: for a walk in shower, how much area is needed from the valves to the walk in opening to prevent splash outs? We have ample space in the bathroom, but really want to use glass block for the interior wall construction, so that limits where we can place the valves.