Bought a cable set with the shutter and had a circle made with the engraving "OIL COOL AIR - Pull = reduce flow" and this was epoxied to the knob with some black epoxy die added. Cable was routed with the cabin heat under the forward baggage bay floor with P-clamps and cable ties.
Knob bracket (photo 2) for Cabin Heat (L) and Oil Cooler Shutter (R) was made from .125 scrap angle with some lightening holes drilled and rivetted to cross brace - very sturdy.
Post Note In the winter I fly with the knob out (shutter closed) and in the spring-autumn period adjust the knob to try and keep oil temp in middle of guage at 180 degrees F.
