Thanks, everyone, for the helpful feedback. I had it at 6.5. At a first quick look it appears to be around the 8.0 mark in terms of gloss, no signs of writing, tears, missing pieces, stains or long color breaks. On closer look, there are minor short color break lines on the front cover which lower the grade to 7.0 or 7.5, and then the condition of the corners take it to 6.5. I wasn't sure how to adjust for the triangle-shaped defect but based on the feedback I'm getting I think it would fall within the 6.5 grade.
I also did not count off for the rough cutting along the open page edge of the back because it's minor and clearly from a dull cutting edge (production issue). It doesn't even affect the presentation value of the book. Overall a pretty book with nice centering, strong colors, no distributor marks and hardly any spine stress issues.