I am not sure I understand the issue. It doesn't matter what the grain looks like, because it's the texture of the screen that's important. For drawing, sketching, reading, the image is fine, it's the resistance to the pencil that's important. It's why you buy either the Bellemond and / or RPP.
The quality of the image isn't really an issue. At least I don't find it an issue. You aren't using either of these screen protectors as long term screen protectors. They are both removable. So when I am done for the day and want to play some games or watch videos, I remove the screen protector easily. I get the full clarity of the 13in iPP, and the next day I put the screen protector on & get back to work.