Interesting stuff, thanks for posting. If I'm reading these charts correctly the parallel valve engines need something like 25-30% more cooling air to achieve the same CHT as the parallel valve?
On the other hand it would seem that the total heat production for the angle valve engine must be as great or greater than the parallel valve, assuming the same combustion temperature. This implies that the CHT cooling advantage of the angle valve must be balanced somewhere else, presumably in greater need for airflow to the oil cooler? If so then you still need tight baffles, if the oil cooler takes its air from above the engine.