Can't help you on laying the Altro floor but I insulated the floor of my T5 with Silent coat to add some mass, which stops it creating noise, then I used three cheap roll mats ( In leiu of mass loaded vinyl) cut up to cover every square inch of the floor, except the wooden battens which were used to hold the ply flooring down. I then put a genuine Kombi rubber floor mat on top of that and it worked very well.