ATX02

my box is 46.5"x24"x24" and i have 2 18s btls on dtr3400, i want to put my subs on top and ports facing back, i have a 98 plymouth voyager, how big should my ports be, i want to use 2 10" aero ports @34hz, should i use aero ports or something else? how does the square inch work for the port area, can some one help me design it