An RTA is very helpful. Anything that you are comfortable with will work. I am quite fond of the new Phonic PAA-2. It is affordable, has a real-time RTA, built in calibrated mic, phase testing and XLR inputs and outputs for equipment testing. It's also very compact and portable.
As far as EQ, I hear this all the time. I think that good room treatment addresses entirely different issues than an EQ. We don't make room treatment to alter db levels in a room. That is an inevitable result of reducing acoustic distortion. Reducing distortion is what our products are made to do. Once you have achieved that, you can properly apply some EQ if desired to balance your frequency spectrum. But only using EQ is only adjusting the volume level of your music and its related distortion, which in my opinion, is missing the boat.
As far as the room treatment appropriate for your room, I would suggest 8 of the Framed Response controllers, 2 in each corner, in black of course with the corner mount brackets. This will reduce most of the distortion from the main 4 floor->ceiling corners. You would also benefit tremendously from two Framed Responses horizontally in the corner above the screen.
