Definitely don't lose the seams, but Slobodan's right on darkening the shadows.
OK then if I want to darken the shadows on the right I think I can do the larger area but what about the railing? What I find happens is that I get a weird effect with fuzzy edges. What's they way to go about that?
Looking at it again I think that the right hand should be left just as it is - it adds a third level of complexity with its shading. Darkening that area would make it too much like the left hand side of the image and lose that element of subtlety.