Have a look at Raimondi RLS levelling system, used this system recently, (first time using a levelling system). Had no issues with it, simple to use , once you got a handle on the wedge tension.
Basically I had a bungalow on a hill and have built a 3 storey extension in front of it. It's been a massive undertaking and very complicated. Access is really limited and I can't get deliveries to the site. Including concrete. So hence the tiles.
I'm inclined to agree with Ajax123; for such a large area instead of concrete effect/look tiles just wet pour the whole area with concrete then polish it!
Why spend circa £6k + on tiles to look like something when you can have the real thing.........half the cost!