My thoughts...
With stainless I use a cut off wheel to cut the line, and then dress the end from there. There is a consensus that tubing cutters work harden the end of stainless tubing and can crack. With that said, I had used a quality tubing cutter in the past for years without issues, your mileage may vary.
I use AN fittings when I build stainless brake lines which are 37 degree vs 45 degree. With 37 degree I do a single flare. Use a quality tool (mine is a
Ridgid). If you think you're going to do more of this in the future for fuel lines or future projects and the budget allows I just picked up a flare lapping tool from
Koul Tools, leaves a perfect sealing surface on the stainless flare.
In the past I still had stubborn fittings that leaked (before I used the lapping tool), so now I just use
conical an washers on all the AN connections. They come in aluminum and brass, and the softness of the washers allows the connection to seal even if there is a small imperfection in the stainless flare. I do this automatically to prevent any leak issues when I go to fill and bleed the system, cheap insurance.