After submitting the car for the first race, I dedicate some time to think about the rules (LDVH would say "to read the rule book for the first time" and he would not be completely wrong).
I think that the rule K4.1 is too restricrive: since we have a very good and realistic model of the radiators, thanks to OpenFoam and MantiumWFlow, the only rules should be the required flow, the radiator angle (in order to simplify the use of porous media) and the radiator vertical position (we do not simulate the real wheigt distribution, someone could think to place radiators over the engine). I think that the minimum surface areas only makes things more complicated.
Also the 1200mm rule is not useful woth the present rule. I think that a design like the one in the oicture would not be allowed, since the iutlets are not 1200mm far from the inlets:
The inlet minimum area (50000mm2) makes them too big to be placed in front of the car (or in position where the receive a direct 44.7m/s flow), so the must be placed in low pressure areas and... they become bigger