Floor tiles should be smaller in a bathroom. The grout lines help with the slippery factor and it isn't such a hazard. If you're using a large tile like that, then definitely stagger.

It is easier to get a better look if you stagger the floor tiles with that sizing. Also, it gives the eye a rest to have a difference with the two tiles especially if they are the same basic tile. Keep grout same color as tile, or as close as you can.

How can you get the correct slope with those big tiles? I think they are way too big for either application.

Did you mean you are using the 12 x 24's on the floor of the shower? That won't work, suzyq53 is right on that point. You need smaller scale tiles for shower floors, drainage and slipping issues.

yeah, I'm hoping OP meant she is using them for the wall. Hopefully she has mosaic-like tiles for the floor of the shower.

If you stack them in a linear pattern on the shower walls, you can do the same outside of the shower or lay them in a running bond pattern. Either one would be ok.

here is an example. they did a running bond pattern in the shower and outside, on the floor. Notice the smaller floor tiles for inside the shower.

1939 Brick Colonial · More Info

Corliss Residence · More Info

However, in a curbless shower, they run the same large tiles. Obviously these are very matte to avoid slipping.

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this one they ran them stacked in shower and running bond on the floor. Looks good

Master Bathroom · More Info

I hate to disagree with the experts, but it is possible to use large format tiles in showers. It's certainly done where I live, in Australia: I have them in my own shower. In my case, the tiles were cut on the diagonal to fit them to the slope leading to a central drain. Ours is very similar to this:

Cornwall Gardens, Kensington · More Info

Here are two more:

Contemporary Bathroom · More Info

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This is how it's done:

From: https://www.houzz.com.au/discussions/using-diagonal-cuts-to-slope-your-shower-floor-planning-guide-dsvw-vd~635709

I suspect it requires above average skill sets from the tile setter, though. And I believe it's not done very often in the US. Incidentally, we've had the house for 18 months, used the shower daily, and never had a slipping problem.

You can also use a linear drain, which requires less finicky work by the tiler.

Right, but what's the point of using big tiles if you are going to cut them up? Everyone wants less grout.

didn't say you couldn't use them, you can if they are matte (as opposed to glossy and slick). They do it like that in the hotels in Vegas as well! And it is slippery! But I suppose it's easier to clean than all the little grout lines.

it's not a misconception. some people just prefer it because of the slipping hazard. No one is saying it must be done with small tiles. The other issue is getting the larger tiles to lay level when you have a slope on the floor. Some are more pronounced than others.

I like big tile, but you can't cut some of it in circles for the fixtures, Mostly on walls it works great, but not on the faucet wall. And not on the floor unless you have a very slight slope, which requires engineering beyond the usual shower. You really need the perfect layout. Cutting some of these tiles is a known issue.

I know the large format tiles can be cut to fit on slopes and we see it here in commercial bathrooms quite often, but personally, I don't like the look of it at all. It gives the look of "I just bought all the same tile and I have to use it everywhere" feeling! to me at least. I much prefer a complimentary floor tile. Doesn't have to be really small, like penny tiles (not a good example, but just to make the point) but 2" x2" or so works really well. You can also do a pattern with longer tiles say 2" x 10" that works from the center outward, kind of like a square and make that look good, especially if your drain is centered and you do a square drain plate. Just takes tiler skill as stated earlier.

I find it institutional.........but it's better with a linear drain in any scenario, and curbless.