The cheapest flaring tool HF sells will make perfect double flares for a long time as long as you lubricate all of the crush points every use. Most of the time, failure to make good flares isn't the tool.
Lol, I bought the cheapest one I could find, did a few practice flares and figured it out. Built some brake lines and the tool is ready to go again. I'm real happy with it. Tightening down properly and some lubrication made things go smoothly.