What size flare fittings on radiator cooler 727 automatic?

[Scooter]

Getting ready to install a passive transmission cooler after the radiator cooler to assist keeping the 727 from getting to hot. The cooler has 3/8 hose barb fittings on the inlet and outlet ports. Many people have said just slip the 3/8 hose over the flare on the transmission lines, clamp it and be done with it. Not a high pressure circuit from what I understand.

While I was in line waiting to pick up the adapter in the far left of the photo below to do just that, I had an idea to get and actual male and female hose fittings with 3/8 barb on the opposing end. They were just a few bucks and I guesses -6AN would do it. Did I guess correctly or do I have some spare 6AN parts now?