@Mark Oliva- actually, Mark, you gave me EXACTLY the answers I was looking for. Yes, North is at the top of my map... I should perhaps put a compass rose on this map, I didn't really think about it since it's a map of a single structure. And yes, the windows at the top are flat, at least, that's what I'm deciding. Since the light is coming in directly from the West, seems to me that the northern and southern windows would show light at a deeper slant, also, since the light is, in effect, coming in from the side. While the windows on the Western side of the tower, the pools of light would be straighter, more direct, as the light is coming in directly.

Every thing else, is just a matter of transparency and fading... which I already have that set up like what I did for the lights on the stairs, and it looks good to me, so that's what I'm going to go with. Thanks Mark! I know, now, what to do