With the grips attached to the gun, I then began to do the final filing to make them fit perfectly. This took several hours. Eventually, I had to remove the tape from the backstrap.  I filed as carefully as I could, but there was no way to avoid getting some file marks on the gun.  I tried to keep them to a minimum.

When I decided there was no more filing I could do, I got some 600 grit wet/dry sandpaper and went over the backstrap as thoroughly as I could.  Then I got out the 1500 grit and actually began to polish the metal and the new grips. I worked on the polishing for quite a long time while my wife and I watched television.

Eventually, the metal took on a better shine than it had had from the factory.

Note how thin the left grip is at the top--my thumb fits quite comfortably there, and I can keep the gun from jumping when I shoot it. The grip flares out asymmetrically at the bottom, but I find this enables me to hold onto to the gun better.  The new grips are thicker than the old, so there is more to grab hold of.