Judith Collins Thanks so much - very helpful!

custom-tiles.com Helpful hint on tile/grout joint effect on tile installations - your 12x12 tile is probably NOT really 12x12, so if you want to figure accurately enough to size the installation including grout width: know that 'nominal' size (e.g., 12x12) is not the ACTUAL size. Ask or check written specifications for the actual size, try to find out what the average variance of tile size from this figure is. Tumbled tile typically varies the most due to the rounding and chipping at the edges. Tiles with larger variances from the 'average size' require a wider grout line to aid the installer in making adjustments to align the tiles.