My first dehorning project was a Ruger P-85. I used a triangle-cut and a round Needle file. To begin, I knocked all of the sharp edges down with a large file and then just finished with the Needle files. My final task was to match the polish which I did with strips of 400 grit sandpaper glued to popsicle sticks (fingernail files were too rough). Ensure that you thoroughly clean whatever parts you are doing afterwards. I didn't use electrical tape to protect the flats because I am just that good!
I do, however, think it's a great idea for the non-perfect.