I am going to use Leviton QuickPort switch plates and snap-in connectors attached to a piece of 1/4" oak to make two 9" x 18" patch panels. One will be installed in the wall behind the television and one will be wall mounted behind the equipment racks. I will use standard electrical boxes attched to the back of the wall plate. I am trying to decide if it would be better to use metal or plastic boxes? Does anyone think it would matter? If so why? Thanks.