In my RV7, I am using the SJ cowl,standard vans IO360M1b (180hp) baffle mounted 20002a cooler and so far it is cooling well up to 90F OAT. It did not reach 200F until the end of 4 T&G and full WOT/2700 rpm climbs in the pattern.
It was running 195F on a WOT-2500 RPM climb to 17,000 at max gross weight.
I do have a suprisingly good pressure delta across the cooler. (edit) Upper pressures measured with and w/o the oil cooler shutter open showed zero change in pressure and CHT. There is certainly a limit on how much a cooler can flow and not affect the system, balance is important. The 20002a is apparently not pulling enough flow to show that change.
The cooler must be matched to the air mass and pressure available to cool properly, the standard cooler does work for me. That said, I am not sure what temperature would result with a WOT-2700RPM, 80 kt climb @ 100F OAT and full gross. I don't even know what the design climb, OAT, CHT, Oil temp goals are for this engine. If it is 500F CHT, and 270F oil temps, @ 100F OAT, for 3 minutes, then maybe it is good.