With my dedicated NACA duct feed and exhaust vent for the oil cooler, I
wonder
if I will have too much oil cooling.  
Dan

Dan-
You will likely have too much cooling, but that's desirable!
Install a pilot-controllable butterfly valve in oil cooler inlet to throttle
the air flow. You'll then be able to set your oil temp in the 190 degree
range Winter and Summer.
It will likely be nearly fully closed in the Winter and fully open on the
hottest Summer days.
Bill Rumburg
N403WR  (Sonic bOOm)