I've finally had time to get back to these brakes. Could I use Pauls springs and caps? As long as the cap holds the spring in place and the spring moves the arm in the right direction, it should work, right?
If it doesn't bind up the brake arm when you tighten the mounting bolt and everything else lines up, then the Paul's caps should work. Just make sure the caps/springs hold the arms against the back of the canti stud and that the arm doesn't slide back and forth on the stud.