Depending on how far from the wall to your back of your screen, you will never get much real BASS (spelled like the fish, or guitar, or type of low frequency sound, but pronounced like home base, or the guitar, or the low frequency sound
) trapping. You need some good thickness to it, but it would seem that what you want to do is just prevent the wall and the back of the solid screen from becoming a big drum with sound bouncing all around back there.
How much space is between your wall and the back of your screen?
Also, you talk about bass trapping all around your room up to ear height, again, I think that there are some terms getting confused here since you would have quite the massive treatment all around the room where it wouldn't provided a good effect.
Bass traps *generally* just go in wall/wall corners, floor to ceiling to start, then can go into soffits, or along ceiling/wall and floor wall corners. Combating room resonance, reflection points, and so forth happen all around the room, like floor to ear height, etc. I am sure that I am not getting the terms exactly right either, thus my vague description, but it will be easier to get solid advice from the experts here if you at least know that bass trapping isn't an entire wall behind a screen, or floor to ear height around the room so that they can provide the best advice to you.
OC703 is a tried and true material, but as mentioned there are cheaper alternatives that yield similar results like the Roxul 60. A lot of people cover their entire front wall with linacoustic, but again, that is for acoustically transparent applications mainly. I've heard of good results with the "cotton denim insulation" as well, but you need to make a frame for it since it isn't rigid at all.
Again, come back with the distance between the wall and the back of the screen, and people can start helping you eliminate your issues there, then you can look at treating the walls with absorption, diffusion, reflection combinations.