Agree with above post. grout will work at the wall side but wall meets floor cracks nearly 100% of the time so matching colored caulk would be best there. joe

We used large format porcelain tile that was light like yours, and it didn't come with bullnose. Instead of mitering or using Schluter strips, our experienced installer suggested a polished edge. He just used a succession on fine grit wheels mounted on a grinder for all the exposed edges before they were installed. It's incredibly smooth, and blends right in with the grout color we chose. We like it better than the appearance and contrast of adding something like a Schluter strip. If you have a dark surface finish on your tile and the tile body is light, a polished edge might not be the way to go, but what we did worked fine for us.

so the large beige-ish tile is going on the floor and that patterned tile is on the shower wall? can you post a pic of the room? does that large tile come in a 2x2 or 3x3 size? it should. use that. u said it looks busy, but I don't see how. it's a solid look tile. same premise they've done here. used a smaller tile in the same make as the floor introducing any other type of mosaic will look busier. if your large floor tile is a matte finish, it could be cut and used on the shower floor. maybe have it cut in thinner, rectangular strips. they've done it here in the shower

I can only say that all of those are fairly large, and it's imperative that they are dead flat if you want to avoid lippage. The larger a tile is, the more likelihood of some noticeable warping. Having said that, when I remodeled my master bath, we went for 24" X 24" tiles on the bathroom floor, and 12" X 12" tiles on the shower floor and walls (with a linear drain to allow use of such large tiles on the floor). I checked samples of the tiles for flatness in the store before purchase, and checked all of the ones that were delivered before they were installed. I was fortunate that they were all totally flat. The easiest way to check for flatness is to take two tiles, place them face-to-face, and see if you can detect any gapping by looking along all the edges.