Custom fit piston rings / tool?

I have a hand crank piston ring filer and an electric ring filer, have never used the electric one, always using the hand cranker for some weird reason. I always use a soap stone to de burr ALL the edges. Oh oh and a ring squaring tool or at least some calipers are a must.
Help me understand de burr All the edges.

Simply the the 4 sides at the ring ends? (filed areas)
Right?