Before i take the Polycoat off i plan on doing most of the metal work. The irritating beaver tail is first. I use a medium sanding drum to start removing metal and smoothing and reshaping the sharp rear corner.
I remove most of the metal with a medium drum on a Moto-Tool, stopping often and checking my work. After each drum sanding session i shoe polish the whole area with thin strips of 320 cloth backed paper. The shoe shine will let you see the shape of the metal better by taking out the marks and gouges left by the drum, it gives your eyes and even looking surface to look at so you can see any mistakes before continuing.
If you are just looking to remove the irritating edge this is far enough. You can remove more and shape it into an upswept version but if you are just looking to rid the painful red mark on the web of your hand, which on this gun is all i am after, this has gone far enough.