I'm replacing the speakers in an old sailboat with a pair of Rockford RM1562. They're mounted under the seat and are essentially infinite baffle... the seat is open to the cabin below. I'm only wanting to stiffen/deaden the fairly flat, 1/8-1/4" thick fiberglass panes that they're mounted in. The current plan is to just surround the speakers (1' radius or so) with dynamat. Any other tips?