Where the flap attached to the metal frame I used SS self tapping screws with SS fender washers (they are larger in dia) Also used a SS self tapper going into the plastic, most of the weight and strength is coming from the screws into the frame, the screws in the plastic are just there to keep flap up tight against plastic fender for looks mostly. I also used some well nuts where the two fender pieces joined to make it easier to remove if that day would come. I gave the dimensions in a prior post, at the very top you will see where a support gets in the way, I just cut a small notch in the flap to allow it to clear the support. I also added an extra small flap of rubber right in front of the area that holds the modules up near the top of the fender. Just wanted to keep the excess mud and water from getting into that electrical area. The rubber I used was from the farm/home/family store, it is a stall mat for animals, and it is big all for about 20 some bucks. Could make about half dozen mud flaps so if you cut one wrong you have plenty to make over. I worked carefully until I got one just the way I wanted and when I was happy with the fit I just turned it over and made a symmetrical one for the other side.