you might be over-thinking it because you're nervous. totally understandable. with your white cabinets, you have a great opportunity to select both quartz & tile in a similar shade of color, knowing they will all stand on their own characteristics.

go to a good tile store, take a few selections home with you. put the quartzes on the cabinet and the porcelain on the floor. visit them for several days. quartz doesn't have a "busy" pattern like natural granite, so you don't have to worry much about that clashing with the tile.

while you are pondering, make sure you ask your tile installer if he will actually install rectified tile - some won't because they've never heard of it, some won't because it's time consuming to install.

p.s. "rectified" tile is dimensionally stable, allowing smaller joints. typically tile is cut then fired (heated). rectified is fired as a continuous sheet, then cut afterwards. rectified tiles are practically uniform.

Thanks! I'm making some progress toward a decision. I've been to the Dal-Tile showroom 3 times, and I think I'm going with Fabrique in linen, or Monticeto in crema. My contractor wants to use MSI quartz, so if you have any suggestions, they are welcome. I'm taking the tile with me tomorrow when we select quartz, b/c MSI doesn't have samples!