Answer:
When creating a double flare on tubing, it is recommended that the tube extend approximately 1/8 to 1/4 inch above the top of the tubing clamp. This allows for a sufficient amount of material to be flared without creating excess excess material that could potentially cause issues during the flaring process. It is important to properly measure and mark the tubing before beginning the flaring process to ensure that the final result meets the desired specifications.