I can't see them at all.In these two pics, can you notice the mirror image of the glass on the floors? I tried to create the effect of sunlight coming through. I also plan to use a lighting script to make some subtle changes as well.
I don't think that carpets work in a fortress, imo it detracts from any fortress-like feel to the maps. I'm also unsure about the pattern of the floor tile you've chosen. It doesn't, to my eye, look like the sort of thing that you'd find on the floor of a fortress which would, I think, be more regular in shape.
I agree that the beam looks a bit thin. I also think that there's something a bit odd about its perspective. It doesn't look top-down the way it should.