The thicker and denser the FG the better it will absorb sound. LF attenuation needs thick and dense fiber. Packaged home insulation rolls and wads are very dense and they make great absorbers but ugly.
Mattress foam is closed cell foam, so it can't do any attenuation because the air doesn't penetrate. But if you had cushions or bedding that air can flow through it will attenuate sound. But it has to be thick and dense to work on LF.
I would think you can get FG insulation in your tropical climate.
Place the treatment panels that you already have as near to the monitors as possible so that you will absorb as much LF energy as possible while it's still loudest, and before it gets loose into the wild where it is harder to locate and trap. You have a lot of panels, pack them closely around your monitors so that sound can only go toward you and less goes to the surrounding walls and start bouncing. Tritraps in floor/wall and wall/wall corners closest to speakers, with flat panels resting on the tritrap edge leaning against the wall. And panels making a "horn" around the speaker baffle to aim sound at you and minimize side and rear radiation, etc. Use your imagination to experiment with this concept, it works. But like any other acoustic treatment scheme requires a lot of fiddling and fine tuning to get it to sound the way you want. But it's not WAF friendly.
Good luck!
