Roger,
You've got the right idea, but you really don't need to sharpen them.
Here's what I do. First of all, it goes horizontally into the butt, where the cheekpiece and the butt meet.
Figure out where the tabs are going to be located, and drill several 1/16" holes, the depth of those tabs about 1/2 to 3/4 of the width of the tabs, then just drive it in to place. It will be there forever. If you don't pre drill the holes, it will not seat, and you'll bend the $#@* out of it getting it driven in.
Hope that helps.