Originally Posted by
John E
Centerpulls and sidepulls offer comparable leverage -- if they didn't, then the corresponding brake handle travel would differ radically. However, centerpulls offer the benefit of adjustable leverage, achieved by shortening the bell cable (for longer handle travel and greater braking force). This is super easy to do with Mafacs.
For best braking performance, select either centerpulls or sidepulls, but use KoolStop pads, modern low-friction cables and housings, and if you don't mind going non-original, aero brake levers for a 10% boost in braking force.
+1 one one modern pads with aero levels on vintage brakes. For this build I would likely go with the center pulls and aero levers which will likely give the option of running 27 or 700c wheels and enough clearance for bigger tires.