Big lot of these screens for $20/each... useful gobos?

Call out to all the grandmas in your hood and collect some old HEAVY blankets to lay over the gobo things. Less reflections, more absorbtion. Put them up in angles to each other for less "focus" in their reflections.

I didn't look at the frequency absorbtion data but would be suspicious about them anyway. Hard felt surface, that's why you want those 20 blankets to use with them. You may consider airing the blankets if they smell like a dead animal. Or record mostly bands that are heavily into the dead animal thing. You could specialise in death bands and just tell them the blankets are from a mortuary. As long as they don't ask what a mortuary needs blankets for.