[wdfifteen]

Looks like you are getting a good start on an ambitious project. Unless you dig a foundation for the stone that extends below the frost line your stones are always going to move with changes in moisture and temperature. The sooner you start thinking of them as a nice bed of stone on a lake of moving soil the sooner you will understand what you are dealing with. Research what you will put between the pavers. I use polymeric sand, it is flexible and looks good, but between moss growth and weather I have to replace it every 5 years or so. So far I haven't found a good alternative, but I'm open to suggestions.