The image at the top of this post is the original scratch which happened during the inventory process of the empennage kit. This skin was taped to the bottom of the crate and as one of the skins above was raised it was dragged across this lower skin causing what was almost (or was) a scribe mark.
The repair process was per recommendation by AP/IA and can be seen below. Started with 320 grit and then when the scratch was still just barely visible switched to 400. Did the whole process wet as I prefer wet, and it took about 20 minutes.
I do not know how much material it removed but I think a lot less than I expected. Clicking on an image will enlarge it.