I suppose ideally placing the cc on a speaker stand in front of the rack is best, but that would look quite out of place in anything but in a dedicated A/V room, an even then... The only other option in our space in on top of the rack w/ the tv on top of it. I like the current scenario best and it images quite well set at the leading edge of the rack. What you say?
I would like to see the center channel unobstructed by furniture and at ear level ideally.
I used a taller rack for my center channel in the bedroom to get it closer to ear level.
The monitor was mounted on the wall. Since you have a window, one would have to make some serious modifications to keep your system on that wall. Not impossible, but may cause you to rethink your system orientation. Obviously, you still want to keep the overall room dimensions in mind and retain a good seating distance\position.
Like I said, it is never easy. Just depends on your determination and the limitations that one can implement.
I actually sealed up a window in our primary room. No easy way to provide light control so the easiest thing to do was to seal it up. Sometimes the answer is not readily apparent. Creativity can be a blessing.
Just thought I would share some ideas. Thanks for posting and keep us up to date on your progress. We are all here to help.