Oil Temp in winter?

I bought a cover plate kit from Vern a couple of years ago. I rarely need it in SE Texas but it sure helped when I flew through North Texas and into Oklahoma in February a couple of years ago.

I can see how you did that very well in that picture. Thanks. I take it that blocking the airflow entirely is the way to go? The example I say had three holes to allow a percentage of the airflow to continue, but also was told that as the weather got colder those holes could be taped over as needed. So this really helped. Thanks again.

I was shown by my CFI (on his 415C) that he had an aluminum plate with 3 one inch holes screwed over the cowling hole directly beneath the prop spinner. He suggested that I tape a cardboard or plastic cover to block airflow to the oil cooler as an experiment. I am afraid to do that without an IA to okay that. Have you heard of this solution?

As the weather temps have dropped, so has my oil temp. I can't get the temp up to the normal range of 160+. I have a C85 Stroker power plant.

Would it be advisable to cover all or a portion of the airflow into the oil cooler unit?

Overnight temps are barely in the 32-25F range. What happens when it gets really cold?