Your guy is right. Every 15 feet, ad if it's in direct sunlight or subject to extreme temperature change, that drops down to every 12 feet. As for what brand has the best matching caulk, I'd like to say Laticrete, but truth is all three of those would be good choices.

Then there should be no problem. The only problem with large format rectified tile is that it tends to "bow" slightly in the center, so that if you set it in a 50% brick joint, the centers of the tile will always be higher than the edges, causing a definite fail in the "credit card test". But if you're setting it in a standard soldier coursing, there should be no problem.

I've not used Miracle's product, I'm pretty much stuck on Aquamix's Grout Colorant. They have a few more colors than Miracle, you might find one better suited to your needs. Great product, works as advertised.

Thanks Mongo, I spent a long time today at the tile store looking at all the grouts and decided only this so far: set the wall tiles tight with unsanded grout. But I am having a terrible time with picking the type/color for the floor in the shower and the bathroom. I looked at Mapei, Custom and Laticrete (sp?) grays and none look right. Many almost looked purple or blue not silver at all or else they look way to dark against the rest of the floor. The tile store had bunches of people helping me, all women, luckily they were not busy and the general consensus was to pick Customs Snow White for both the silver glass shower floor and the bath floor and the avalance on the walls. Next to the Avalanche the Snow White did look "a little" gray but isn't that still too white for a shower floor that I paid almost $600 for silver glass so I wouldn't have a white floor in the shower!? Ack! Said to do the walls in Mapei "Avalanche" and the lines would disappear because the color was almost dead on and the lines will be tiny. I left there and went to another store and they only carried Customs and the 2 men/owners there said right away-wall tile-bright white, bath floor-snow white and shower floor Platinum. Told me to set the wall AND the floor tile tight-unsanded on the floor and wall both. It took them about 30 seconds but neither store would let me bring home the little sticks so I still don't know what to do. None of them recommended any epoxy (not Spectralock or Opticolor) once they heard my tile guy hadn't done it. Said I did NOT want to be his test case for a glass shower floor. The second store said Customs "polyblend" grout already has mold and mildew inhibitors but will have to be sealed yearly unlike the spectralock. Geez, this is 2008, can't they just put the sealer in the grout already-lol. Please give me your advice! Thanks so much. (I swear this whole bathroom is giving me an ulcer! In CA, so had the hotmop done and while it didn't leak, now it won't drain because of a big puddle lower than the drain's weep holes-ack. Just had the drywall guy finish up and the painter came and did primer and all the tile is here and ready to go but now this-grrrr. Hopefully the hot mop guy will just come out and do more on that lower part but still, another hold up.)