I don't have a problem using compression fittings because the pressure is very low in the line and the steel compression fitting fuel line kits have never leaked on my cars at 70 psi...but, all the compression fittings seem to be for aluminum line so I am not sure they will fit correctly on a steel line or bite hard enough if they are not steel ferules.
I am trying to do the same for a new cooler and new transmission cooler lines