I used to have difficulty trying to level large tiles. I tried tile-leveling spacers, but I stopped using them out of frustration. Then while laying some 19-in. by 19-in. porcelain tiles, I realized that all I needed was a hook to lift a tile that was sitting low. In the trash, I found a piece of 12-ga. cable, stripped its end, and bent one of the wires into a little hook. I made a loop on the other end of the wire in the same direction as the hook so that I would know which way the hook was facing. I slipped the wire between the tiles, made a quarter turn so the hook was under the tile, and lifted. The 12-ga. wire with that small hook was strong enough to pull the tile level without a problem. Once I pulled the low tile up to level, I bent the wire over and taped it to the adjacent tile until the thinset cured.
Vincent C. Pirrone, Sparks, NV