I went with aircraft-style AN fittings when I fabricated the oil cooler lines on my project.
The conversion requires two things.
First you need to prep the oil cooler itself, by drilling and tapping to accept an NPT fitting. The secret is to use a 3/4" step drill.
Then tap
I used a 90 degree fitting to keep the forces down on the radiator fitting.
The other thing you need to do is cut off the barb fitting and braze on -10 fittings onto your oil cooler hard lines.
The hoses are made up using stainless braid -10 hose. These are reusable fittings, so if the hoses ever start to weep, new hose can be done very simply. Here are the hoses ready to be installed.
I'm very happy with the results and the look on the car.