UE4 works better with sizes in multiples of two. (128,256,512,1024 etc) so a size of the 140/200cm is a bit weird, it could translate to 1024/2048 though.
I would make a mesh the same size of the texture size you want and apply a correct uv map to it. that way you know for sure that it fits correctly.
You could also change the UV size of texture-coordinates node to get it more like you want.
The thing is, with meshes and their UV’s it would be guesswork on how the size of your material looks like.