I am currently in the process of building an enclosure for two GNX104's for my '91regular cab Ranger. Based on my dimensions, with 3/4" mdf, my internal volume will be .58 cu. ft. per chamber. How will my subs perform in this enclosure, as i know the specs say .66 cu. ft. Could I get away with using 1/2" mdf for more volume? I also considered fiberglass, but l don't know what an optimum thickness would be for strength, and whether there would be any advantages of using it in my situation. Any ideas?