I didn't see any questions in your post, but the good news is the room is large. I'd other have large and square than small and not square. Office baffles can range from marginally useful to not useful at all. It depends on what they're made of and where you put them. Follow the advice in my Acoustics FAQ linked below and you'll be off to a great start. Here's the short version -
All rooms need:
* Broadband (not tuned) bass traps straddling as many corners as you can manage, including the wall-ceiling corners. More bass traps on the rear wall behind helps even further. You simply cannot have too much bass trapping. Real bass trapping, that is - thin foam and thin fiberglass don't work to a low enough frequency.
* Mid/high frequency absorption at the first reflection points on the side walls and ceiling.
* Some additional amount of mid/high absorption and/or diffusion on any large areas of bare parallel surfaces, such as opposing walls or the ceiling if the floor is reflective. Diffusion on the rear wall behind you is also useful in larger rooms.
For the complete story see my
Acoustics FAQ.There's a lot of additional non-sales technical information on my company's
web site - articles, videos, test tones and other downloads, and much more.
--Ethan