Whats the biggest u can go in the back?

I will be looking to get some rims for my car soon, Im a show car guy but have never owned a chevy let alone a malibu but im wanting to be one sickest bu's around "yall will see soon" but imma try to go staggered and drop it so 20's of course are my choice and so 20x8.5 in the front will 20x9.5 or x10 work for the back? or do we have bad luck and have to get it all even around?

Thanks in advance