Okay
I hauled the Twenty my bride rides out into the light of day today...
This is how the brakes are set up:
I bent the levers a bit, made sure they were at the optimum location for her hands, used Kool Stop Continentals and have the wheels trued to the absolute best I can do, then set the brakes as close to the rims as I could without scrubbing. Result is relatively short brake travel and quick braking. HOWEVER, she doesn't feel comfortable with using dual hand brakes, so the new wheels will be built up using a 3 speed coaster brake hub (most likely a modern one) which is what is on her other bikes.
Aaron