I did the project by cutting the tile openings such that the top and bottom outlet tabs rested on the tile. You can also buy outlet extenders/spacers to offset the depth of the tile. In your case, the second option is best. Note, there two types of extenders: one is literally a very shallow version of the outlet box (can be hard to find), the second is small spacers that fit on the top and bottom screw, between the outlet and box.