[LS short box]

I like the Nicopp line. It flares like butter. I do have the Eastwood flare tool and as said above it's not cheap but works very well.
I ran 3/16" both front and back. I like and use the rubber lined clamps down the frame rail. Not a fan of self tapping screws so I drill the frame rail for clearance holes 10-24 stainless bolts and ny-lock nuts.
Not a great pic but it shows the master and the Nicopp lines.
Don't know what your project direction is but if you are moving the gas tank to the back I paralleled the fuel lines to the brake lines from the tank to the firewall.