It's clear that in order to control the movement of water in the "rain gutter", I need to find some way to control the adhesion of water droplets to the surface. Hence, the sample you see here. It turns out that water adheres even more tenaciously to the the surface of aluminum than bare aluminum. Weird, since it does a great job of making fiberglass layups release from a surface. The other three quadrants weren't much better. I'm going to need to explore some other options.