So, here's the short story about the zig zaggy things. They are actually precision rack (30 microns), that are scrap from work. I basically used them to replace worn cutting edges.
Here is the long story. Many years ago, my neighbor borrowed the drag and never brought it back. The good news, he dragged the road whenever it needed it. The bad news, he almost wore it out. I originally built it with 3" angle iron blades. I had intended to flip them when they wore down to 2". He wore some of them down to 1".
So I salvaged what I could, bolted on a few new 2 1/2" sections, and bolted on cutting edges over worn sections. It originally had some weight boxes on it, but they trapped debris (leaves, etc.). When I was able to get that scrap rack (2"x3"x 1 miter), it was the perfect solution for robust cutting bars and weight.
Because I crown the road, all the weight and wear is on the right hand side. The rest doesn't wear too bad. The ends of the two rear blades wear a bit over time which is perfect because it helps feather the edges.
I could have put the scalloped edges down to act as scarifiers, but I really don't need it to be that aggressive. I have a box blade I could use for that if I needed to, or I could bolt a scarifier blade to the drag if I wanted to.
I don't know if the video shows it, but that drag really leaves a nice smooth finish, and that guide wheel maintains the crown.
I see CNC in your handle. We have three 11 axis CNC Mill Turn machines in our plant.