Hey man! Thanks for the review! You are right, it is my first time shipping floppy comics and yes, it's a learning process! I will improve, thank you for the honest criticism--I seriously welcome it because now I can improve the next time I ship floppy comics!
I use s-165, that's a box that has several bend points so you can adjust it. I don't know if it'll work for a single book. I do as you did I bag and board my books and then I use one strip of bubble wrap and then I pack it in the box. Maybe I'll do a video on best packaging practices. I hope this helps. If you have any more questions let me know.