Moving the pivot point on the brake pedal

I have done that modification many times. However in your case, I doubt you will gain enough benefit to provide satisfactory braking. You need to move the prod hole closer to the pedal pivot, but you would need to move it so far that the prod will be at a bad angle.
For maximum transfer of leg power to the m/c, the angle between the pedal centers & prod needs to be 90*, brakes applied; you will lose that changing the pivot.
As others have said, a smaller m/c is a better fix; but you will also have more pedal travel.
Best fix is a booster.