I am getting ready to put cultured stone over a fireplace with a zero clearance prefab insert. I have the metal lath up over the entire fireplace where the stubs are but am not sure what to do around the wide black face of the insert. I know you can finish all the way up to the opening with non-combustible materials, but I don't know how to attach the metal lath to the metal face of the insert. Can I use metal screws and screw right through the face? Do I even need the lath over the metal? Any help would be greatly appreciated.