Yes, you can get copper/nickel in 1/2", I got mine at Summit, it was around $86. for 25 ft. $50. something for 3/8". Yes, I used AN flared nuts and sleeves on it for fittings. You do have to have an AN flaring tool, I have one, built an airplane. In difficult bend areas I used SS braided line or AN fittings. My new car is an old race car, so my fuel feed and return lines are routed a little differently, 1/2" and 3/8"", but all doable and doesn't look bad.
1/2" Feed line, # 8 AN
3/8" Return line, #6 AN. Yes this size through the fitting is close to 1/4".
Regular tubing bender
Having said all of this, if I had a normal car, I would just get it all from Inline tube or some other mfr. Think that we have lost the OP here! Sorry!