Tubing question

I have to step down the fittings to the line lock. And to reduce the amounts of fittings I would have to use I'm using a prefab piece of tubing withe the flairs and fittings on it. I haven't been able to find a prefab piece of tubing with 12-20 fitting on one end and a 7/16-24 fitting on the other side in 3/16". Hope that makes sense.

NOW I gotcha. Lines with those special sized nuts are factory only. You have several choices

1--Use step up/ down adaptors

2--Use different sized line(s) to get the nut size you need

3--Cut old nuts off old tube and reflair

4--Obtain new nuts from different sources, IE where you can find 'em. NAPA has some, and cut and reflair the new line.

5--EDIT turns out I don't know how to spell "flare"