What I did is just apply the dynamat as if the holes weren't there. As you are applying it though mark the holes with a permanent marker cause you wont be able to see them when it's on. If you press the dynamat on good enough you should be able to see the holes. Use your utility knife and cut an X in the hole then push the panel back on. It's gonna be kinda tight because of the dynamat, but that's good because you know for certain that that piece isn't gonna rattle either.