By dull edge, I meant something like the back of a butter knife. You don't want to actually cut the quill, just make a series of very shallow dents about 1/4 to 1/2 inch apart. They won't noticeably weaken the feather. If you don't like the effect you can always steam the feathers and they will go right back like they were.
I have never been bold enough to do this for competition because I don't know what the judges would say about the little dents, but the overall effect and the amount of control that you get from this method makes the results FAR superior to those from curling irons and etc, especially from a normal viewing distance.
In my opinion.
