Tboooe, As my room is on the small side 12x19,I went with the Mondo's(6")thick for the extra bass trapping.
2'X2' module on the bottom and 2'x4'Mondo on top.
They sit on top of each other so no more holes in the walls.
Plus I spaced them away from the wall boundaries(4")for more free trapping.
The HF Mondos are at speaker reflections(two per side)the rest are the regular Mondos.
17 stacked Mondo modules in all an she's not to dead.
Three diffusor modules on the back wall.