I bought some Owens Corning 703. Now what?

@shalommorgan
That's an inspiring effort and a beautiful setup you have. Thank you so much for sharing that, along with your advice. I just spend an hour or so moving things around and so my side walls became my front and rear wall. Terrible -- lots more bass problems and harsh highs. I'm going back to listening across the room width - I have no side reflection issues that way.

I'll take your advice about not expecting too much with a few panels. I do realize that a large amount of a room needs coverage and that my ceilings pose an ineliminable problem. I'm experimenting to learn, but your room now shines out as an ideal!

You have the gift of room volume/ space. No level of acoustic treatment can make up for lack of room volume. Experimenting is a means to an end. Enjoy the journey. Yes, set expectations accordingly, but don't settle for less than what you think is possible. 

Your system seems to appreciate more side room/ width to breath. I really think your room is pretty good as is. Again, I think a few diffusion and/ or absorption panels well placed is the right call, but no need to get to deep in the weeds with it. No need to cover larger amounts of your room. Don't forget the ceiling as you work through it. Again, be surgical in your use and placement. Address what can be addressed before you hit the threshold of diminishing returns.  Also, consider adding a bass array setup to help address low frequency modal issues, if needed. It really helped my room. Google (bass array) Earl Geddes - using multiple subwoofers, if you want. 

Best. 

Experiment to learn is good in concert with science. Did you post a RT60 ? 
Enjoy your journey:-)

how deep are the joists above ? This is a hint....