It looks good. I was lazy and used one of those brush wall plates for mine.

For the grounding, you can get a small piece of copper flat bar. It’s not that expensive and will give a good, solid ground connection to the bulkhead connectors passing through it. You can through bolt a ground lug to the copper bar to connect the ground cable to.

Also, a tip for installing old work boxes. There are 4 small holes in the corner. Hold the front of the box against the wall and poke a small nail through the holes, then use a straight edge to draw lines between them. That will perfectly mark the hole you need to cut out.