Your rock guard looks great. You will get a lot of good info from this site.
Now to get to my post. My rock guard is about 1 to 1/2 inches from the ground while traveling. There is even less at the top. Here are 2 pictures of rocks that ended up in the area between the engine area and windshield. Since I had a front windshield cover, I had no damage to the front windshield. That being said I did have damage to other areas of the tow vehicle from the rocks
. The area that I got all the rocks and damage, I could only go about 25 MPH or slower. Please don't expect your rock guard to stop rocks from kicking up at your vehicle
. You will need to protect the tow vehicle even more, than just a rock guard. Safe travels....