The light looks really good. Regarding the light artifacts, I recall seeing them in my tcad imported model as well. Don't know how to fix that.
Regarding the profiles, I've turned straight line segments into members for crown molding, etc, but when I tried that with arcs, my only choices were walls or retaining walls, footings and edgings, so I tried it with walls but I didn't get too far. I've had some success taking my tcad models into sketchup and replacing some of the features with much fewer facets. I'm learning to draw arcs with few polygons and revolve 2D figures with few polygons...