Refusing to give up, I gave the bowl a final coat of Waterlox. This time, I wiped the bowl down thoroughly with mineral spirits until no specks at all were visible, strained the Waterlox to get rid of any steel wool particles I had inadvertently introduced, and used a disposable foam brush. I worked on the inside first, going over the sections until no dry spots were visible, and mopping up excess liquid from around the circumference of the base.
Then, I elevated the bowl on a small piece of wood, and worked on the outside. I left it overnight at the community shop, which is air conditioned, and picked it up the next morning. In a few weeks, when the finish has fully cured, I will give it a final rubdown.
I'm pleased with the way it came out, but the first time using any new product is always a bit hair-raising.