I am at the point in my project where I lay the tile.
I am really glad I slowed down and thought about this now. As I am laying out some tiles for installation, I am noticing that the tiles are not flat and they “rock”. After further examination, I notice that the tiles are not the problem. The tiles are perfectly flat. The floor is not. It turns out, this type of tile requires a standard of flatness that simply does not existin most floors. The tiles are 36″ long and 6″ wide. This accentuates the flaws in the floor. Thicker adhesive will not correct the problem. Wider grount lines will help a little but not enough.
Making the floor flatter is a whole new level of work that I am unpreparred to do.
My proposed solution. Cut the tile from 36″ to 18″ on those section that “rock” in order to give the high spot someplace to go.
Second alternative: use the small flexibility inherent in the tile to bend it and glue it down solid. I don’t think this will work. I think it will come up over time, or even crack during normal shrink/expansion of temperature changes.
If I had it to do all over again, I would have gone with smaller tiles. But then, I didn’t get a choice.