Just something to consider - if the crates weren't super old when you put him in them you can contact the company and see if you can get a replacement. I had a foster hound/collie mix that broke out of an airline carrier in my apartment, ended up eating an entire 8kg bag of dog food and some other things that made him pretty sick. I emailed the company about it and while they denied that the crate was for leaving the dog in unattended (hello, airline crate?!) they did ship me a new one at their cost to a local store to trade the broken one for. I didn't need the crate after he left, I had bought it just for him, so I ended up just donating it to the rescue, but it's something to consider.
Have you tried a thundershirt as well? When we first got Bru the only things that helped to take some of the edge off were the thundershirt, a DAP collar and DAP diffuser in the room where his crate was. The pet store calming collars and diffusers didn't work, but the DAP ones did. One of my dachshunds was extremely dog aggressive on leash but when we had the thundershirt on him it helped a lot, we don't need to use it on him anymore now.