Anyway, the recipe says bake for 10 minutes at 400, and they turn out really juicy and runny. So I decided to try doing that with half of them, and just running them under the broiler until toasty with the other half. The broiled ones definitely have great texture, and the cheese got nice and brown. But it seems baking may have brought out the basil a bit more, and made the flavors meld better. So the jury's still out.
(Also, I salted the tomatoes and let them sit for a while to draw out juice, but they needed more rinsing. The end slices, which only got salt on one side, were definitely better.)