Mark S.
I may not be the one to answer; because I consider my oiling cooling to be marginal. I see only about 12 degree temp drop across the cooler, and about 120 increase in the air temp; clearly indicative of marginal air flow. However; I do get adequate cooling at cruise of 150-160 KIAS the oil temp runs 190-195 with OAT at 75 – 85F. In full power climb at 120-130 KIAS the temp will get to 220F by the time I've climbed 3000' AGL, but that's a climb rate close to 2000 fpm; so I can pull back the power some shortly after takeoff and keep the temp below 220.
I've reshaped the diffuser inlet to the cooler, and sealed all the leakage around the cooler, and it made little noticeable difference in the cooling. Apparently the airflow before the inlet is a bit messed up by the gear doors; and I may have to make the scoop inlet area larger.
Al