Last year I used the rubric provided by @kaugie here. It seemed to work pretty well - the students who put in a decent amount of effort got decent scores, and the ones who flew through it putting in minimal effort… usually didn't. I didn't check to see how well it lined up with the changes for this year, but it shouldn't be too far off.
However, one thing I did notice was that several of my students had found the solution PDFs on the main DS Challenge page. So be aware of that when you're grading, and however you want to deal with it.