I'd have to see the overall design.

I like the idea of large hex floor, and you could do a cube backsplash in the mcm colors.

just like this one

Or, do a larger hex and something like this

but again, all depends on your decor choices

for a mid century design, I really like this one. the backsplash will be more of a design piece, so make that the star.

Cube design backsplash is the epitome of mid century. I love this choice

https://mercurymosaics.com/blogs/shop-by-kitchens

check out some of the kitchens where they make some of these tiles

Modwalls:

https://www.modwalls.com/pages/kitchen-inspirations

and fireclay tile also makes similar tiles

You could do a 14" hex floor w/this design, but the wood floor also looks good.

or so a 24x24 porcelain tile.

Again, depends on the cabs, the countertops, lighting, layout, etc.

if you doing in your face colors, I'd keep the flooring on the down low. maybe a charcoal large hex. nothing too busy.

but a cool terrazzo tile would look amazing w/this design too. like this one:

and if I haven't convoluted your choice enough, I'll thrown in the color issue.

here's large hex cement tile for the backsplash w/a wood floor. all the elements make this lean MCM, and the black and white just steals the show. I love this one w/the wood

Thanks, Beth!

The house was built in the 1960's so we are trying to be true to the era but also add a sophisticated twist.

Here is one idea for a hexagon type backsplash we are considering.

My thought is that this should be paired with a large format darker tile that coordinates.

But I keep coming back to the hexagon floor, which would make our long galley kitchen appear less long.

I don't think I can get away with the above backsplash and a hexagon tile floor. What are your thoughts?

Here is a picture of our long galley kitchen.

We have lived with this busy flagstone floor for quite some time and don't mind the texture or pattern. What we dislike is the blue/green color and that there is too much going on in the pattern. Our thought was the a hexigon floor would be much more sophisticated and updated while also providing a toned down design. But we are open to feedback.

We also are considering this hexigon backsplash.

But my daughter made the same comment you did that she thought it looked like it belonged in a bathroom.

I also feel that way.

Amd for that reason, I would use it for the backsplash.

Are the ceiling/beams remaining as is? If so I think you need to find a way to tie in that rustic look, and I'm not sure hex tile (as much as I love it) is the answer.

The ceiling beams are remaining and we have them all over the house. It isn't really a rustic look so much as an open concept northwest look.

Our goal is to make the kitchen look sophisticated, not rustic.

your 'hex' is exactly the same as my cube backsplashes I posted. I mean, yes, they have 6 sides, but because of the pattern they look like cubes. (they're actually diamonds or rhomboids fit together to make this pattern)

The ones you want for the floor have no design and are a true hexagonal tile.

just like this one I posted

It' looks straight out of the 60's w/a more modern flair. I wouldn't use the larger cubes for your splash. do something in this size

That flagstone you have is original. (if you had it professionally stripped, cleaned and redone, it might look pretty good.) I will tell you, getting that removed is going to be a bear.

and if you stripped the white paint from your ceiling, you'd fine some fine wood hiding underneath.

It's a cute kitchen. look up mcm style or 1960 redone galley kitchens and get ideas.

I'd redo the ceiling and bring it back if possible.

I'd also do cabinets like shown above. do the hex floor and the white cube splash. bring in color w/accessories. period appropriate but modern.

this is not mcm. at all. It's modern style in all gray. mid century was about color and natural wood.

the only thing slightly retro about this kitchen is the cube backsplash. if you like, there are plenty of places to order it. Too much gray for my taste. (but if you keep your flagstone floor, that kitchen will tie in great)

We also have an aesthetic that nods to the mcm ...with a little pottery barn/ scandinavian/glam mix just to keep it fresh ;)
and I stumbled on these:

Merola Tile Porto Savona Hex 9-7 / 8 in. x 8-5 / 8 in. Dandelion Porcelain Floor and Wall Tile (11.56 sq. ft. / case)
https://www.homedepot.com/p/Merola-Tile-Porto-Savona-Hex-9-7-8-in-x-8-5-8-in-Dandelion-Porcelain-Floor-and-Wall-Tile-11-56-sq-ft-case-FCDPSVDX/312682908

Unfortunately they're only in a handful of colors but the patterns you can make are really cool. The second and third photos are terrazzo (which I'm currently having a brief love affair with ) hex tile. Good luck! Can't wait to see what you decide.