I waited almost five weeks, but it was worth in the effort.
Mounting: super easy. A board do not purchase the recommended glue on different website selling this product, I bought glue for Acrylic ceiling tile in casto to 4.5 € cartridge and AC like nickel!
I positioned the tiles above the clew and in opposition to the carpet.

Usage: I listened to it again all my mix and the result is surprising. We feel that there is more 'floating' in the bass, the sound seems more direct and less blur. My listening area is 3m x 3m, these are very adverse conditions and the addition of ceiling tiles to really improve listening. I recommend it highly for those who like me small environment.
You can see pictures of my setup here: http://pagesperso-orange.fr/gemine/ then menu 'studio'.