[ERASER5]

Since it has not been mentioned, you are using a Double Flare kit, right? That Cunifer tubing should be easy to bend properly.

The big key to doing good double flares is tube prep. The end of the tube must be square. The outer edge must be chamfered. The tube must extend exactly the correct above the clamp. There is a ring on the bump tool to gauge the stick out. Put a little oil on the bump tool as well as the flare point, not on the tube (oil on the tube can make the tube slip in the clamp). I like to hold the tube clamp in my vise if possible. This makes it easier to form the double flare.