They look good. As expected, they do little in the low mid and nothing to the bass area, but that is normal, and it shows on the graph I asked from the Thomann seller.
Probably a 10 or yet better 20 cm thick rockwool (50 kg/m3) is better if you have the space for it. I have the space for it, but wanted to have many different absorber panels, to have more even broadband absorption, and used them to build mobile panels.