Received my custom one today, the size is really nice, but it's clearly thicker than the one designed for the 16", so I won't be using it. I had requested they use the same material as the stock size for the 16", but this is definitely thicker like the material for the 2012-2015 models.
I also started thinking, sure this prevents key marks on the screen, but because it only covers the keyboard, any pressure on the lid while in a sleeve during transport or what have you can still depress the entire Radtech/keyboard, resulting in marks from the edges of the keyboard frame and trackpad, so that's sort of a bummer - don't have that problem with the full size Radtechs from the 2015 and older models.
So even if you have these keyboard covers, still be wary of pressure on the lid or you'll still get marks on the screen, they just won't be key marks.