Is the Platinum the Laticrete Platinum? If so what about Silver Shadow? It is a very soft gray that is almost white, but looks great with Platinum. Are you using cementitious grout or epoxy? I know many have used SS for their light or white tiles. Here is Silver Shadow epoxy on the bottom vertical grout spaces. The top area was grouted with a 50/50 ratio of Platinum and SS. The middle row was with Raven and SS. Note that there is a halo around the marble, like it is still wet. Epoxy can do that with marble, I just looked at my tile boards after over a month of drying and the halo is still slightly there with the darker grouts. But not as marked as in this picture. So that is something to consider. Here is the Silver Shadow epoxy with my bright white tiles. With these tiles the SS looks light gray, but with the tiles above it looks almost too white for my taste: I took Laticrete epoxy Platinum and mixed it with a little bit of Silver Shadow for an in between gray for my black slate floors. It is in a 3:1 ratio. The colors mixed very nicely. The grout sample on the left is the SS and the one on the right is the Platinum. It didn't take much SS to lighten it up significantly. If I did this over I would just have used Platinum. My DH really likes the combo. He thinks it ties in with the tub. It is relative isn't it, because it is not white at all but appears white. I will be having a marble listello, as seen above in the sample board, with my white tile wainscot. I might mask the marble off when I grout the white field tile with Silver Shadow. Then I would plan to come back and grout the marble with a reverse blend of Silver Shadow 3parts to Platinum 1 part. Nothing like trying to complicate things. That's one of the benefits with DIY. But if I was paying someone to grout, I would not consider these mixes.

Yes...this can be evaporation of water. The mortar has plenty of water in it. It needs to "dry" before this is considered "set". The only place for it to escape = the edges. It can take several WEEKS for this look to go away. Weeks - not days. If you have stopped work, then you might as well leave it for a few more days to prove to yourself that it is "getting better". Weeks. Just remind yourself of that every day that you look at it.

Not a great grout. Pretty much the lowest common denominator as far as product goes. Were it me, I'd have it removed and replace it with Prism from Homer's. Antimicrobial and holds colour quite true.....

I am not a designer and am just a person with an opinion. I like any of the three floor patterns, but each has a different “vibe.” The stacked one is very modern. The running bond (yes, 50/50 staggered) is classic, but in a large format tile it will seem modern, too. The horizontal/vertical layout resembles a zig-zag a bit and I think it can break up the length, but at 7 ft wide and with fixtures like a vanity and tub, I wonder if the pattern will look apparent or simply random in your bathroom. You may want to get some graph paper, draw the floor of the room with the fixtures in place, then “lay out” your “tile” on the drawing’s floor to see where the individual tiles will go and if you like the pattern it makes. Try starting the layout of the tile from both ends and see if it makes a difference. Don’t bother with spacing in grout lines, just draw each individual tile. See what the floor would look like. I agree that a simple white counter will be best. Or gray. But look for solid color or minimal veins so that you do not have to compete with patterns elsewhere.