To make your cage more even, just be sure to use all of the connectors that came with your cubes. If you ran out, you can even order more from this site. When I ran out, I used zip ties (as I see you have) but just make sure that they're pulled really tight. My only other advice is to make sure that the cage is supported well. That may be why some of your grids are sagging. Hoped that helped. The cage really does look great and I'm sure your piggies are happy!
