Regards the "what is happening to you" as being some theory that "hotter water in equals hotter water out" is, as I say, only part of the story. It's the inability of the cooling system to keep up with the heat source. So, either your cooling system has some defect where it isn't working as designed or the engine is generating heat in excess of it's design. These cars were engineered with a significant "safety margin" between how much heat the engine could generate and how much heat the cooling system could shed, even in instances where ambient heat and humidity were very high. It isn't the "hotter water in" that is the issue, it's the capacity of the cooling part of the system.No ones even mentioned the consensus the 4 rows over 3 is a diminishing return compared to 3 over 2.
But seriously, the smartest and hardest professions ask questions that strive for a single correct answer. If my questions are answered i can put them into an infallible and logical syllogism that might prove I am wrong in spite of my anecdotal evidence. i'm ok with that..
As far as "will the heat pulling capacity of the radiator decrease or increase in relation to volume" question.... if you mean "volume" as in flow rate the answer is neither. If you mean volume as in the amount of fluid capacity of the radiator itself, with all other factors being equal (surface area, fin count, etc.) then the answer is still "neither". If you mean volume as in radiator surface area then the answer is, obviously, cooling capacity is increased. We have to stop thinking of coolant as individual molecules moving through the system. A good parallel is a closed electrical circuit with voltage being equal to the pressure in the system (how hard the water pump is pushing the coolant through), amperage being the rate of flow through the system, and resistance being the coolant passages that need to be followed. You can't increase the flow (amperage) without affecting pressure (voltage) or resistance. Since resistance is more or less a constant (other than thermostat actuation) it's pressure that will be affected.