I'M SCARED OF SOUND LEAKING OUT THROUGH MY ROOF!!!!!!!!!!!!

Hi, I am building a new 2 roomed studio from scratch, and I have the walls and floor pretty much sorted, but I still have my doubts about the ceiling and roof! Here are my plans for it; 6x2 wooden joists will be put on the outer concrete block walls. A layer of chipboard will then be nailed onto the joists for an extra layer of mass. Then a layer of felt to keep the moisture which might get through the tiles out, and 2x1 wooden battens will then be nailed onto the chipboard and into the 6x2 joists. Thick roofing tiles will be put onto the 2x1 battens. Then rockwool will be put between the 6x2 joists. Donnacona board will then be nailed onto the 6x2 wooden joists to keep the rockwool held up. Then an acoustical channel will be drilled onto the donnacona board to separate the layer of drywall to finish the ceiling. The drywall layer will then be drilled onto the acoustical channel. By the way, now that I know the materials I need, I have no clue what brands of the materials and specs I need! If someone could give my some of the good brands and types of the materials, it would be hugely appriciated! Especially for the likes of the rockwool, acoustical channel, donnacona board, drywall, and nails/screws I should be using, And isolation clips! And I am based in Co. Cork, Ireland, incase anyone has some places where good materials at good prices are sold. Thanks, Mark.

Just thinking, Would it be worth taking the donnacona board out and leaving a bigger gap between the insulation and the drywall? Or would it not be worth taking out a layer of mass?