4" x4" tiles layed on a shower floor look great! This is my preferred tile size for working with a Kerdi Drain. If you choose a smaller tile insure that the fleece backer does not break down with water - many do. I believe this water based glue used for the backer introduces a food source for mould growth in your shower floor and makes for a poor install - this should be avoided. The better mosiac sheets are bonded with products not affected by water. We grade all our showers to prepare a smooth surface for our waterproofing. You will not want a 1/16" - 1/8" grout joint when working with a 4"x4" tile. I like 3/16" - 1/4" if the tile has no eased edge and 1/8" - 3/16" if it does. Your tile layout is your first step in a shower bathroom layout. You need to determine this for exact drain placement and shower fixtures which should line up with the floors grout lines if a matching wall tile is being used. I like to set the floor tile with as little thinset as possible and used my grout float to even out the floor tile into the pitched positions. Often we will ease the Kerdi drain a little below the subfloor and we leave the tiles around the drain out the first day and set these a day or two later. My setter on our higher end projects has no problem with the entire floor in a day but I find with my lesser skill set that I can do a better job not trying to do it all at once. I have tried setting the tiles around the drain first and then the next day setting the floor but find the other way around makes for a better install and one where I can nail the Kerdi drain's trim height exactly a 1/16" below the neighboring tile. Good Luck! Here is a picture of a Kerdi Drain installed with 4"x4" tumbled Black Italian Marble. The entire floor is a shower pan and even water spilled at the vanity and toilet will drain to the shower's 2" drain line.

I was hoping to find something a little more "special." Since the big orange box sells that it's pretty played around here. Can I put plain unglazed on a floor with crackle glazed on a wall? I def. want a period look, but it doesn't have to be 100% authentic. The floor itself (in the master) is only about 3x9, not including the shower and separate water closet. (5 feet will be the tub on one side and the sinks on the other, so will have some type of mat.)

My tile contractor, who lives next door, says that he much prefers 4x4. He feels that the 6x6 is just not the right scale. He has also been installing quite a bit of subway tile lately. These are just his opinions, but I thought I'd pass them along. I had a designer tell me to go 12x12 as well, but I agree, I don't care for the look. His theroy was that when you do 4x4 of 6x6 in the field tile, it is hard to differentiate in the focal point behind the range if you want to do something different there. With 12x12, you basically get one tile, then two pieces in a normal back splash. I guess I am going 4x4.

Daltile sells 4 1/4 x 4 1/4 cove base tile. http://products.daltile.com/series.cfm?seriesName=semigloss. So does American Olean. Typically the tile size includes the grout joint so I perhaps that is actually what you want