Just an interesting ditch bucket on the internet- never seen one before https://imgur.com/t/mildly_interesting/PA7j8J8
That is pretty cool...better not have many rocks in the soil if you are using it.
I’ve made some with similar idea for grading low flow channels in retention basins. Tags ,you are correct about needing the right soil
That would be good for the final pass after you get it close. One wrong move on an excavator that size and you will fold that bucket like closing a book.