I recently stripped both my rear calipers,painted them,fitted new seals and refitted them.
Before i did all that they worked perfectly as did the handbrake.After refitting with new discs,pads and bearings the footbrake worked fine but the handbrake was very poor.After use thought it has adjusted itself and now works fine.
Have you tried pulling the handbrake on and off about 50 times so it adjusts itself ?.