How do you know if you have "enough" radiator?

rad thickness more important than number of cores... min. 2"
clutch fans typically turn at about 80% of crank speed and you may over heat in traffic where airflow is low.
lots to consider here...pulley size,water pump speed,thermostat, fan size,pitch and shroud all factors as well as clean block heads and rad,engine compression etc..
think cooling system....