Just a little advice from the peanut gallery here... Whatever calipers you are using, find the piston diameters of the master and the rear wheel cylinders for that same system. Also you want to make sure the rear drums are the same size as the transplant or you should consider changing them out too. You might already be there, but just in case... The piston sizes are what causes you to multiply force to the brakes, if you mess with them you will have brakes that apply too weak or too strong. It would be a bad thing for the front and back to not be matched. Using a donor car, you could have taken the entire system... even if it wasn't all bolt on you would have easy reference pieces and the combination/proportioning valve to match the system, even if it didn't match the car.
Mixing and matching brake components is a little dicey because its a critical safety system. Other than finding parts to fit physically, the diameters of all the pistons are matched for force and travel. It is possible to not have enough pedal travel with a system not designed to be there. Imagine hitting the brakes hard and your pedal reaching the floor without a hydraulic failure... you may find you need other pieces like pedal assemblies to make it all come together.
If your careful and very critical of your results, you should be ok. Just stay away from "good enough" mentality... brakes are too critical.
