I was able to try out a couple basecoats before settling on my final one:
First, two coats of Krylon Clamshell White Primer/Paint… then the realization that it matched the countertop of my kitchen too closely.
Second, two coats of Rust-o-leum Vintage White Gloss enamel… then the realization that it matched the off-white of the countertop outlets.
Third, two coats of Rust-o-leum Driftwood Semi-Gloss enamel, with a few coats of Gloss Automotive Enamel… then the realization that the Driftwood grey was too… grey.
Finally, in a stroke of indecision and impatience to use the grinder, I sanded down some of the previous layers with 400 grit, then settled on a can of white Appliance Epoxy.