The ' corner bass traps ' floor to ceiling may introduce issues in terms of balance.
Tackling 20 - 200 Hz will be the most difficult but a relatively low reduction in level should be smooth enough.
Absorption behind the ' mains ' should help a bit as well.
My sense of a rooms ' sound ' tells me that diffusion on the side walls could be a better solution than absorption.
Even absorption on one side and diffusion on the opposite wall at first reflection points - ' A Symmetric ' could be effective.
Tackling 20 - 200 Hz will be the most difficult but a relatively low reduction in level should be smooth enough.
Absorption behind the ' mains ' should help a bit as well.
My sense of a rooms ' sound ' tells me that diffusion on the side walls could be a better solution than absorption.
Even absorption on one side and diffusion on the opposite wall at first reflection points - ' A Symmetric ' could be effective.