So, I looked at it more closely yesterday. I was able to force the IPhone 12 Pro Max with the leather apple case down against the charging pad, but, it was very tight.
I think opening up the frame 1/16” should be enough so that it will fit nicely. Or, find a thinner skin/case for the phone. This would be preferred over filing the sides of the charging pad frame down.
Just ordered a “Peel” case that claims it is only .35mm thick. I will post the results in a few weeks when I get it.