Hmmm, I have a set of Mafac Racers, but haven't installed them yet
Anyway, what kind of levers do you have on the other end? I noticed that I have problem with flex with my front centerpulls on one bike, taking up valuable pull. I still need to resolve it. The other issue I've run into is too little pull with my brake levers.
If you're using some kind of aero brake levers, there are a lot of choices available.
A few possible adjustments. Make sure the wheels are true, and the pads are reasonably close to the rims.
Yoke length.
Short Yoke: Requires more pull, but tighter at the brakes, I think.
Long Yoke: Requires less pull, but less pressure at the brakes.
Squeaking is always a thorn in my side. Perhaps it will go away with more use (and maybe get grippier as the pads break in). You could sand or file the pads slightly to change their profile.