I have made some adjustments to the Google Sheet I created. Namely in the Image Gallery tab. It was getting frustrating to have to individually move and shift every image and cell to properly place a new image when one has been added to the visual novel. As such, I've arranged the sheet so the images are in a single list rather than trying to keep them in their '6 per page' format they were in in the visual novel itself. The images will still appear in their proper order, but this will make it easier for me to add in future images as more come out.
Also the main page will now list what version I currently have the Sheet updated to, and what, if anything, has been updated in the sheet itself. As of this post, it us current up to Version 0.75, Haruki's most recent update, which has one new image to unlock.
Please remember, however, this is not an official guide to the VN, and should not be taken as such. These are just what I have found, or have been told, through my time of playing the VN.