So here is the soil-scraper thing I made. A close-up first... The aluminum plate has 2.5" to dig in. And it is definitely sturdy.
The board isn't warped; that's a macro camera setting effect. It's a 2"x10"x4' board; heavy and straight.
Here it is upside down so you can see it. Its wider than the lawn mower.
Here it is as used. The front of the board and the aluminum plate both help drag soil around from the high spots to the low ones. I didn't plan for the board to help, I just got lucky.
Sorry I don't have a "before" picture, but imagine 6" deep furrows... Here is the "after" picture.
There are mower treads there, but there is 4" of soft soil under it. I will soak the soil with a lawn sprinkler and then transplant some existing tall perennials before scattering wildflower seeds. I have 250" of plastic edging to define the wildflower area.