Do you do some highway driving or is it all short trip driving? Assuming that it's at least some highway driving, say once a week, then you could run just about any oil in that car & not have problems.
Tranny oil, then that's a different story.
The oil cooler fitting would take the place of the factory oil switch adapter. Located on the engine, under the carbs. Has one wire going to it. The new adapter will have the switch port, and a in-out set of fittings, to loop up to your cooler.