Absorption/Diffusion ER points

Hey, my home studio is a small room. At the early reflection points, I have a drywall on the left and a window on the right. I've started experimenting with covering the window to reduce reflections. As many have suggested using absorption at early reflection points, I tried placing a GIK 244 panel on both sides, but it completely killed the room's perception. I actually preferred the glass over these panels on the side. What do you think is the best solution? Should I go for a thinner absorption panel or a thin scatter plate? Thanks.