Why lose the space underneath the APM. you can use that for other stuff :-) This is only one corner. All thanks go to GuyMcCaldin who initially designed the anti vibration mountI left some room for the rest of the earplug. Hence the larger diameter. The screw holes are for M2.5. Added a smaller version for the dampeners you can buy. repositioned the screw holes 10mm from center of large hole on both the sizes. Drill your holes in the deck 1mm larger then both will fit else the large one will have a misalignment of 0.3mm ....if and when you change from large to small