If no one gets back to you try the John Bridge Tile Forum. It is where I go for all my tile questions.

I don't know your level of experience with tile but large format tiles can be tricky. what you are trying to do with laying the tile in a running bond pattern is a recipe for disaster for a novice. It looks the best but performs the worst. No tile is 100% flat. This is why the 1/3 layout works best. Im a professional contractor and when i MUST lay a 12x24 in a running bond i use a tile leveling system to get them as flat as possible with little to no lippage.. But even with the leveling system there is still lippage from the tiles not being perfectly flat. Also the larger the grout with the more u can hide. An 1/8 joint is the smallest i like to go with large tile.

We've done a far amount of tiling [well, my husband has] and as others have said, not tile is perfectly level which is why you're going to want to have a level so you can level each tile as you go. It's hard, slow work and the bigger the tile, the harder it is to work with as rdamatoconstruction said. We went with the 1/8" grout lines, and it looks good.

Go to youtube and watch videos on tiling. There are some very good ones with pros showing how to do just about anything you can think of. My husband watched tons of them when we were getting ready to tile our kitchen and related areas. They answered his questions and gave him the confidence to do it, and it looks like we hired it done.

Thanks for the quick responses. I am not laying the tile. My contractor has professional tilers. I'm concerned about the instructions I give them. I know there are a few ways to tackle any problem. One may be to reject the tile because it must be laid in a way that defeats the marble look. I would have preferred no grout lines and a straight or running bond pattern. If this is not good for the product. I don't know what is the limit of what I can accept.

What did you end up doing? I'm thinking of getting ATLAS Concorde CALACATTA for my bathroom