Taking my own thread off-topic again.

On the Schwinn, before investing >$250 in a wheel build around a drum brake, I'm going to try a modern dual-pivot caliper and see if that's sufficient. The bike already has an alloy front wheel, not steel, so it shouldn't be too bad. I have a Tekro R559 caliper on order ($23 on amazon.) If that's still hot garbage, there's still the option for a drum brake wheel.

On the new bike, I upgraded the front rollerbrake to a BR-C6000-F. It's much stronger than the original brake -- whether that's because this one's newer, or larger, I can't say. But it stops quick!! I added some rollerbrake grease in case there wasn't enough in there from the factory. This bike just needs a pannier rack, a non-awful saddle, non-incredibly-slippy pedals, non-decaying-foam-rubber grips, and a new stem to lower the handlebars and then it'll join the active commute fleet.