what brake flare tool should i buy

I've had the same KD Tool flaring set in my box for 40 years. Still works like new. Make sure to get a good bending tool for tight turns. Most aftermarket lines, either straight or in a roll have a higher soft metal content and are easy to bend by hand, exempt for very tight bends. I often will buy lines already flared in whatever length, then cut one end down to suit my needs and reflare. This also allows for different size nuts on each end of the same line. Or even reuse original odd end flare nuts.