The cooling performance of the radiator's surface area will not be it's deciding factor since the fans you use on it will determine hoe effectively the heat can be dissipated as well as the fin density on said radiators. You should
read this section(though the entire sticky needs a read).
I would go for the thicker radiator since it will often be the one that has lowest FPI meaning you can get away with lower RPM fans with good static pressure to dissipate the heat.
Pass on your full system's specs and what you intend to cool with those radiators