First you now will have a wet floor alwaays in the bathroonm was that a plan . IMO curbless showers are only needed if you have seious mobility issues like in a wheelchair . There certainly were none in MCM homes . I have a MCM 1956 ranch IN no way do I want a 1956 bathroom in style or function so maybe at least post pics of the tile and IMO all the way up to to the ceiling in a shower and without seeing the tile who knows. MCM homes rarely had wood ceiling or beams in the bathroom either so maybe post a couple of pics of the rest of the house .

Hi there, post some pictures of the room and tile and example of the shower etc. That woukd help others help you.

Also, I’m a personal fan of curbless/ walkin showers. Alot of asian housholds have that and basically the whole bathroom is a shower and is easily cleaned with a slight slope that drains. I wish my house had that feature! How easy woukd it be to just scrub & spray the whole bathroom clean!

Plus, if you are designing for aging in place, I think this is a great feature!

I cannot soeak for what true MCM design is, but if it goes, it doesnt have to be authentic unless you want it to.