I tested my King by doing the dollar bill test on the stove door at these positions,12,3,6,and 9 O'clock, absolutely no give whatsoever, but tried the same test on the door's upper right-hand corner, and the bill could be pulled with lots of force almost to the point of tearing. Am I good to go, no decrease in efficiency or burn times noted, glass stays clean,and after a slow burn glass is only slightly hazed white in that V shape.