Tsst, the only problem with that cage that I see is the lack of coating on the wires. Rat pee can be TERRIBLE on galvanized metal. Just something to keep in mind.
I had one galvanized cage, and I had to use something specific on it to clean it and then rinse/dry really well. It may have been vinegar. Don't remember.
I used to run Little Villains Rattery, had quite a few rats, up to 30 at one time. 5 groups of 2 or 3 males (and one giant rescue male who DID NOT like other rats) and a cage of 12 girls. Girls are interior decorators, and HILARIOUS to watch. Boys are furry slugs, good for cuddling.
I never had any live past 2 and a half, some that lived MUCH less (kidney tumors, lung tumors, myco infections, etc etc).
One other thing I always liked was putting a normal brick under the water bottle so that they had to hop up on it to get the water. It was JUST abrasive enough to get the points off of their claws, and helped absorb any dripping water and avoid fouling the bedding.
Harlan Teklad or Mazuri blocks were all I fed as staples, and then treats galore. Use glass water bottles, just trust me.
I built a 3-part giant melamine cage on wheels with multiple levels and hardware clothe on the back and the front that worked pretty well, multiple levels per cage. I don't have any pictures though.
Good luck! I loved my rats, but I watched too many die.
