What temperature was the boiler running at? The amount of heat you can get out of it is somewhat dependent on the temperature the outlet is set to. Were all of the baseboards getting hot water coming in? Do you have thermometers on the outlet and inlet sides to the boiler? Do you know what they read? Was the boiler actually firing continuously?
Were you able to keep the house warm last winter? What size boiler did you take out? Measuring the baseboard length isn't a good way to determine what the house needs, but it is an approximation of how much heat a boiler could output in the house.