On Torres its right in that miscellaneous section with "woofer" and "bracing". Missed that your "common port walls" figure was empty too so that will give you a little more airspace (assuming you're running the port along the enclosure wall) as will moving to 3/4" material. I didn't see woofer displacement on the Skar website but found one site that gave it as 0.15cu/ft per woofer. You may want to confirm that number though. I don't imagine it's far off though my X15 is 0.2 and it's a fair bit bigger.