Der friend,
Do not use clay litter. It sounds economical but it actually ends up costing more then a good quality clumping brand because you have to change it. It also dvelopes a horrible odor from urine. Many cats, being fastideous in nature, will refuse to use it once it had been soiled. Leave the top off the box and get the largest box available for your big girl. When she urinated the litter will form a ball that you can just scoop out and remove leaving the remainder fresh smelling and clean. I personally like fresh step because it has little odor removing crystals and a nice fresh smell but there are many other good ones on the market as well.
Please let me know if you still have any questions. I am happy to help.
Warmest best wishes,
Terri
Dedicated to Cats and the people who love them!
Please press ACCEPT if my answer was helpful and leave feedback Thank you! Terri