You can see the problem, I am sure.
What is in each binder? Might as roll 1d100 to see what I get when I grab one. I decided to print labels for them using Google Docs. Well, there is a horizontal but no vertical ruler.
Annoying.
In an effort to fix this, I made a template with an image of a ruler on each axis of the page. I trimmed the image down to read from 1/4 of an inch to 10 1/2 inches. On the other one, I ended at 8 1/4. It roughly takes into account a quarter inch margin all around and a 48 pt font.
It worked nicely and now I know what books I have.
You can download the template on Drive.
Speaking of books on DriveThruRPG, you could download my book: Zero to Hero: Uncommon Commoners. It's pay-what-you-want and compatible with many OSR D&D type games. It contains over 50 commoner character classes, rules for using the commoner class as a professional skill for PCs and many other game ideas.
While you are there, why don't you leave a review. Feedback is always appreciated.