This looks really nice SG. Being a stained glass artist my eyes went straight to those parts and other than the same window being used it looks pretty good. I know there are not too many options so that's all cool though. As far as the reflection on the floor, don't make it so accurate, blur it out a bunch...usually we just see color splotches.

As far as lighting goes there's 2 types of light I deal with...transmitted light (light that comes through) and reflected light (light that bounces off) and whichever light source is stronger will dominate (which is why stained glass doesn't look good from the outside the sun bounces off but on the inside the weaker lights there allow the sun's light to pass through). There are 3 types of glass we use opaque (no light passes through so we use that in mosaics), translucent or cathedral (all light passes through no matter the color), and opalescent (light glows more than bounces off or passes through so we use these most often in lamps and in Tiffany style windows). This last method wasn't even developed until the 19th century so we can throw that out and the first one is useless in windows so that leaves cathedral glass. In the northern hemisphere, windows that face the south get the strongest light and windows on the north get the weakest light. Now if this is a night time scene then it would all depend on moonlight and torches vs. interior lighting. If there are no torches on the outside then these lil reflections would be virtually unseen unless all of the torches were off and then the whole reflection would be more white-ish...exactly as you have here but more blurred out.

So now that the class is over (sorry for rambling) I like it alot.