I'm starting to expand my repertoire with the PM Grind and I'm really happy I'm doing it.
At first I solely used my PM 60 around the green (where it excels!) And even then only for open face shots. From there I started using it for some square-face chips & pitches and discovered it also excels there, just make sure to keep the shaft leaning forward and strike ball first.
Lately I've been using it on some longer shots up to 50 or 60 yards, usually with an open face. These are a TON of fun to hit with it and they give me ridiculous stopping power.
I love using my 58 for those square face chips around the green. It's almost automatic if I keep that weight forward and maintain shaft lean like you said. The shots out of the fringe are some of my favorite with this iron.