Fin baseboard radiates heat in a different manner than CI radiators. The spec sheet on fin radiators will indicate how much heat per foot it produces at any specific temperature. You'd need a heat loss analysis to see how much actual heat that room needs, then match the length of the fin radiators to the heat requirement. Same thing with the CI radiator. Depending on the temp you run the water in the boiler and the heat loss of the room, you may need to raise it to get the needed heat with the available wall space for the heaters.