Radiator Face Area
As we have seen, cooling air becomes warmer as it passes through the radiator. Coolant in the back row of a radiator is cooled by warmer cooling air that coolant in the front row of a radiator. Increasing the face area of a radiator exposes more coolant to the coolest ambient cooling air, increasing the radiator heat transfer capability.
Increasing the face area of the radiator by making the radiator larger will help.  Removing obstructions in front or behind the radiator in order to expose more radiator face area to ambient cooling air will also help. HyperFlow radiators do have increased thickness, while this is not the most efficient heat transfer design, for MX Race bikes this is critical to improve flow and reject additional heat.