Tips on making your own transmission lines

I used steel line, and I believe it was 5/16. It was from a roll. We just bent it the way we wanted it and flared the ends. Can't tell you the fitting size, but I run a GM tranny anyway. I ran them to the core s
Support and flared the ends and ran hose to the tranny cooler for ease of disassembly if I ever need to pull the radiator.