@eufl the trims only cut inside alongside the opening, not the outer wall, so you can shift + sledgehammer them along the inner walls if you like, they will only disappear there then, not on the outside. I did this below (used both a frieze and a trim outside)
https://i.imgur.com/VegrW2F.png
I think weather might be a bigger issue though, probably freezing in the non-room hallway with snow on the railing and everything lol. Love basegame?....
Also, friezes do appear on the inside of the outer wall and do pose an issue. Spandrels would not be a solution either, as they get lowered because the friezes are present x.X. I am starting to see why you decided on your workaround...