I bought a Stone stomper 2 years ago before our trip to Cape York and couldn’t be happier with their help working out initial dimensions and quality of work. While they keep the rocks down, I also believe it helped reduce the dust recirculating back into the car.
Up the Cape I came across many homemade versions and around 60% of them were either broken or big holes in the mesh.
I did consider making a row of truck mud flaps on a bar connected to the Towbar, but I was put off by reading reviews of poor fuel consumption or heat problems under the car.