If you get to a bike shop or online catelog you may find some of those red rubber brake pads for your center pulls. There are a few different grades of those pads where some are softer and some harder to give different grip to the brakes. With those installed and adjusted spot on....and your cables adjusted
properly it may be all you'll need.
Certainly none of us want to over drive our braking capacity. In Ohio 20 mph is the legal limit we can travel.