Chad,
In response to your question about where to place 6 panels, I will give you two different answers. The answers differ based on what your primary desire is for your acoustic treatment.
Option One: Absorbing First Reflections
If this is your primary desire, then place 1 panel each on the left and right side walls at the first reflection points (you may need to move some posters). To know the correct location, follow the instructions given here:
http://www.realtraps.com/rfz.htm . Next, place 1 panel each behind your left and right main speakers (or you could place 2 panels on the theater's rear wall). Finally, place two panels on the ceiling to absorb first reflections there.
Option Two: Bass Trapping
If your main desire is to absorb low frequencies then use your panels to make corner bass traps. I am guessing that your ceiling height is just under 7 feet. Use 3 panels in each to stradel your front corners from floor to ceiling. Double up the panels to make them 4 inches thick. Let me add a suggestion that you consider buying more panels and making more than just two traps if you do want to bass trap your room. Ideally, you would place traps in the two front corners, the front corner next to your built in equipment rack, the rear corner where the standing lamp is currently located and maybe along the wall/ceiling corner under the sofitt.
Six panels is not enough to do both, and looking at your room, I am not sure it would be enough to effectivley bass trap your room. I would suggest that if you can only go with 6 panels, you use them to absorb first reflections. Then, as soon as you are able, start getting more panels and add bass traps. There are a ton of examples of DIY absorbers and bass traps on the home audio acoustics page at this forum. Look there for ideas. Hope this helps.