Raspberry Pi 3B case with 40mm fan to fit Kintaro heatsink

I really like the Kintaro heatsinks, but I don't like the idea of attaching them to the Pi via the screws they include in the box that are presumably supposed to pass through the Pi & then bite into a plastic case beneath - because then whenever you remove the Pi from the case, you run the risk of the heatsink sliding around or falling off & getting messy thermal transfer compound everywhere.

Instead I attach them to the Pi with M2 nuts & bolts, however that means that the base of the Pi is r