Notching the HS404, study the drawing and be sure to round the corners. No sharp turns or angles which will cause cracks. I used a Dremmel tool and carefully cut the flanges. A band saw would have cut the time down dramatically
The fluting process to straighten the ribs is a cumulative process. The rib will curve back toward your hand at the point that you are fluting. Just make small indentations along the rib - if it needs it. Test the fit and bend abit more if needed. I found that some of the ribs only required a slight amount of fluting. If you over flute the rib it will start to distort in the opposite direction and will require a hand seemer to flatten the flutes. Much better to go slowly and gradualy get to the final point.
