For most radiators I would suggest a fan with a Pressure rating over 2 mm water. In the 120mm fan size by Noctua, their NF-A12x25 PWM is spec'd at 2.34 mm, the NF-F12 PWM is better at 2.61 mm. Probably that would suffice. Some might consider the iPPC line as overkill, but the NF-F12 iPPC2000 PWM model has a spec of 3.94 mm, quite a bit higher and certainly able to do your job. Likely it will deliver about 30% more airflow than the NF-F12 PWM model. The 3000 RPM version is much higher but not really needed for you. You will be aware that the iPPC fans are louder that their regular fans because they are doing much more work. To some extent that will be reduced because that fan does not have to run at as high a speed as the "regular" fans to produce the same actual air flow.
Just to help understand the specs, a fan's Air Flow rating is the MAX flow it creates at full speed against NO backpressure (airflow resistance). Actual airflow is reduced by anything in the path that interferes, producing a backpressure effect. The Pressure rating is the max backpressure against which the fan can actually produce some airflow - there is no airflow if backpressure is greater. Very roughly if you sketch out a graph of airflow versus backpressure it is a straight line from max flow at zero backpresure to no flow at the specified Pressure limit.