The double and triple pass radiators come from the circle track racing people. The concept is the coolant flows through the radiator like normal, but then passes through it a 2nd or a 3rd time, at about the same flow rate as a single pass. The process lowers the coolant temp leaving the radiator significantly without slowing the coolant flow.

If you really want to test a cooling system, test it in circle track racing.

In a 50 or 100 lap feature event, the motor runs wide open for 3/4 of each lap. The other 1/4 its either slowing down dramatically, or under its greatest load, lap after lap. Air flow through the radiator is always a challenge, often the "traffic" in front of you is right at your front bumper, and generally, the opining for the air flow is kept to the minimum to increase the aerodynamics if no one is in front of you. If that 100 lap feature event is held on a 1/4 mile track, the motor is running like that for 25 straight miles, if the track is bigger, its even more miles. Should the race be halted for any reason, the delay is probably worse for the cooling system, because the delay would be too short to cool anything down, and the delay may result in a total stop, sit and wait, to resume. It would be about the same as running down the highway at 100 mph pushing the car in front of you for 12 1/2 miles on a curvy road with 40 mph turns every 1/8 mile, then stopping at a long traffic light in some small town, the turn around on the same road resume the race at 100 mph speed on that same curvy road, pushing the car in front of you, for the rest of the 25 mile trip.

Any double or triple flow radiators I've seen were all aluminum. They will not look anywhere near OEM if that is a concern, and you may have to alter your inlet or outlet hose configuration.

If the OEM look is important, your options disappear quickly.