1911’s can be tough to rack if you are a little low on the hand strength side. One technique a young lady taught me: Point the pistol down straight in front of you but 90* left (A$$ U Me ing) your right handed) so your trigger finger is up (and off the trigger). Grasp the slide with the left hand. Rotate your upper body to the right about 45*. By keeping your arms straight the rotation will "shorten your left arm and increase the length of the right in relation to the gun, thereby racking the slide. Providing you can hang on to the slide. Be aware if you are square to the range you will come dangerously close to pointing sideways across the range. I suggest you talk a half step forward with your right foot, then step back when done.
That half step forward and half step back was the “unusual movement” that lead me to the young lady that taught me that trick, as such you may have to explain it to someone on the range if it works for you and you use it.
Chamfer is “cutting an angle into a otherwise straight surface to break the edge”. You will hear it commonly when talking about reloading rifle ammo where they “Chamfer” the mouth of the case to allow easier seating of the boolet.
In this case as you noted the back side of the ears where the plug seats. The tool needed is a flat file,preferably fine toothed. MANDATORY: one side of the file must have a non-cutting/smooth edge. This way you can just knock the ears down a little bit to get things moving without changing the diameter of your bushing.
If your bushing is REALLY tight in the slide now might be a good time to grab a green scrubby pad and polish the outside bearing surface of the back of the bushing. A simple twisting motion in opposite directions with both hands will smooth it right out.
I’ve been accused of being verbose. It is however incredibly difficult to draw a picture with words so I do the best I can to explain it fully.