A friend of mine found out about the screw length when he mounted visors on his Cobra.
UPS brought him four windshields that were cracked when he opened them.
When the fifth one came, he had them hold it for pickup so he could open it at the counter as the supplier had hinted that he was breaking them.. So when he arrives at UPS, they bring out the windshield (packaged up), and the UPS personel proceeds to drop it on it's side edge from about 8 inches, and everyone standing there clearly heard it break.
Sixth time was the charm though
