Double flaring tool is a great investment, I would recomend spending a few extra bucks and getting a good quality tool vs a cheapy. I have a Snap-on that I've been using for probably 20 years or so, and it still works excellent. Matt, I might suggest an extra peice of tubing and practice the technique of double flaring before you try it on the final product. Double flaring is not difficult, once you get the hang of it, I'm sure you'll use it on everything you flare. It makes a much better flare, way more resistent to leaking.