I'm honestly passionate about this topic. For a while, around the time that urinals started to appear without water, I dealt with some serious splashback issues. I forget when I started aiming for the back of the urinal. I'm assuming that's the deflection angle the paper discusses. At one point I realized, I was sometimes getting some pretty bad splashback. Perhaps because I stood close to the urinal. So I asked a colleague. He said he aims for the hole, and was confused why anyone would piss on the back of the urinal. I started doing that -- problem solved. I am for a direct hit, every time. The problem is that some urinals have a protector over the hole to prevent really smart people and children from putting paper towels in there. That thing is dome shaped, and multiplexes the stream like a lawn sprinker.

All of this, would not be necessary, if there were water at the bottom of the urinal.