I'll be installing an old Jotul 602 in an older coal fireplace. Maybe 1/2 the stove will sit inside of the fireplace opening, which is masonry on an outside wall. I'm trying to figure out what would be the best way to get that heat into the room. I'll be making a block-off plate, insulating the chimney. I'm wondering if lining the fireplace with durock covered with some reflective steel or something would help...or if there's a better solution, or don't worry about it.