I want to make individual boxes for my RF power HX2 12", but in the RF book says that it is recommended venteded 2.5ft3 (70.8L) and this are the sizes: H = 18", W = 20.5", D = 17", with 2 ports-(2), 4" X 12.65"long, but if you guys have another size or a better box with or without vent, please let me know!!