Nice system and room setup.
I used 3 GIK panels on the ceiling. They were purchased some time ago. See them here. The two outer panels are 100% absorption for 1st reflection points. The center panel has absorption/diffusion. They are suspended using eye hooks and wire. They were recommended by GIK. You may ask them for a solution.
You could make the soffit symmetrical down the center of the room, but that is a lot work.
I used 3 GIK panels on the ceiling. They were purchased some time ago. See them here. The two outer panels are 100% absorption for 1st reflection points. The center panel has absorption/diffusion. They are suspended using eye hooks and wire. They were recommended by GIK. You may ask them for a solution.
You could make the soffit symmetrical down the center of the room, but that is a lot work.