Since visual isn’t a good indicator of level or flat I might perform a test.
The zero surface is relative to the head height and nothing else. With power off… Place several playing cards or something similar at a corner of the honeycomb. Tape a Popsicle stick vertically to the side of the head so that it just touches the playing cards. (The playing cards are to provide a known spacer height above the honeycomb without having to drag the Popsicle stick across the grate.) Gently move the head to another place on the honeycomb and see if the approximate height above the honeycomb remains the same. I have no idea if it will vary by 1 card or 7 cards but it will give you an idea of the variance. You can measure the differences of the combined cards with a pair of calipers.
Or you can clamp a digital indicator to the mounting plate like I did. But most people don’t have one of those handy.