I am (hopefully) getting a cat, or maybe fostering kittens! I tried to make a lid for my 3X3, and when I tried to put it on, it sagged horribly. I have no idea how to make it work. What my plan was is to have it overlapping a teensy bit, and then have it fold onto the back 1/3of the cage, where it wouldn't be in the way. Any ideas or tips on how to make it work?!