Can someone give me the screw hole diameter of the 15" Fi BL? I saw the outer diameter was 15.625" but did not see a screw hole diameter. I am working with limited height and don't want the screws to be lined up on one of the boxes wall. Hoping I can save around a 0.5" inch on the height just having the outer surround overlay on the outer 3/4" edge of the box. Thank you for any help! I would measure it myself but I am ordering the woofer in the next few days and want to start the build now.