It's really down to personal preference. I don't like Zorb, I found it heavy and it took longer to dry than cotton wadding. I know other members love it though. If you use a mattress protector you need to use a good quality one, cheap ones go thin very quickly with the amount of washing they get. I don't like waterproof liners, the urine doesn't soak through and if the middle layer gets saturated it will stay soggy on top. I've found it's better to use fleece on the bottom and top with an absorbent layer sandwiched between. You can use newspaper or puppy pads on the base of the cage in case urine soaks through the liner (happens very rarely to mine). Maybe make some pee pads with a mixture of materials to try them out first. The other thing I've found is not to use very cheap fleece blankets for the fleece, these don't stand up to a lot of washing. A good anti pill fleece off the roll is better quality, I get mine from ebay.