Maybe this houzz quote suggests a gray not too cool, or too warm: "select a trim color - if painting walls a cool color (greens, blues, purples or grays), find a white that reads cooler. Put swatches of white paints next to one another and see how they compare; some will appear more warm or beige-like, and others very light gray with hints of green, blue or purple."

I have an all white bathroom but the walls (which started out white 20 years ago) are now painted green so maybe you can get some color on the walls

Going to the ceiling is best' can't tell from photos if windows are at same height, plus you also have the shower head to cover (it never looks finished when the shower head is above the the tile part).

is this for a tub? That large tile, it's going under the tub on this cement board? or is this a shower floor? I hope its not a shower floor! That wood curb also needs to be completely covered. Can we see how the shower is being formatted for the waterproofing? what if you stacked the large tile on the floor? basically like this. (I think it's too large for that small space. there's going to be a lot of cuts, which is a waste for this large format tile) any chance of doing something diff on the floor? diff tile altogether? you're doing the plain white tile on the wall, the hex on the shower floor, and then you have the small space for the other tile? is the shower tile going in like this? (you'll notice the square tiles on either side in the white) you could do a larger hex tile (this is a 2") and use it for all of the floors. you doing a niche? w/the hex tile? I did this layout for my neighbor. used a recycled white glass tile for the niche. (it's not green) or, do a larger, darker hex or something like this gray I'd rather use a longer tile for the shower, like this. can you get that tile in a larger size? you could use this tile on the outside floor in a herringbone or some other layout even this size is better. looks like a 3x12. you could do this on the floor in a diff type of layout I like this basketweave layout or, try a terrazzo look 24x24 size tile for the floors