I just retiled the bath, with the exception of under the toliet. How do I make things level so that when I set the toliet back I won't crack the ceramic tile? (I've had this problem before) Can I shim under the tile before I bond it? Or can I shim the toliet? Do I level the floor? How do I ensure that everything surrounding the toliet is equally level? Tell me in terms I can understand--I'm a simpleton. Thanks!