The glass flange on the slide-in is about 1/4" too high and the feet are all the way down.
I cut the pad off the foot.
Then kiss it with a belt sander to round the bottom a bit.
I always go corner-to-corner with my level in addition to front-to-back and side-to-side. In this case it shows the homeowner his choices. Since the top is not installed level and on plane, he can have the glass somewhat follow the top, making the gap the smallest, but his eggs may slide to one side of his frying pan, or he can have the glass top installed level and let the gap fall where it may.
The 1/4" gap is gone, but the glass top isn't perfectly level. He's happy.
Q