Transmission cooler line help

To make it easy on yourself you can just use a flaring tool and put an inverted flare on the line, same as your fuel line. Use these fittings for the transmission and the radiator (if both are stock)

GAR-48IC5X2 1/8 NPT to 1/2-20 Inverted Flare 5/16 Hard Brake Line Brass Adapt | eBay