Step 4: Making the nose cone.
Take the 1" rubber stopper and trim the base to 11/16 of an inch. This can be done by trimming a groove around the base. Just imagine cutting out a 1/8" thick washer out of the base that is 1/8" wide. Or in simpler terms, cause part of the base to fit just inside the tube of the rocket for 1/8". If I manage to upload some illustrations, understanding this will be easier. I would use a razor, and you will likely need a file.
If you have success with this, then you can use a tough pair of heavy duty scissors to shape the top of the stopper into an oblique shape. This looks very choppy, so I recommend a different method. However, you can try smoothing it out with a file.
If all this goes well (Then I am amazed), then screw the metal eye into the center of the base of the cone. Give it several good twists. Attach the rubber band to the metal eye with a slip knot as your shock cord.