Thanks for this guide... I managed to mod my Ninja (Rev. B).
I couldn't find any of those fancy knobs around, so I used wing-nuts instead, which actually worked out pretty well. My layout of each screw went:
(bottom)screw -> 4 washers + 1 insulated washer -> (thru mobo) thru heatsink mounting hole -> 1 washer -> spring -> 1 washer -> wing-nut.
I have about 8-10 degrees drop.