Dark Rock 4 clips for second fan don't fit on heatsink

[fr0sty]

The two sets of clips that come with it are different sizes, though looking at the heatsink there's no reason for one set to be longer, the smaller ones fit on both sides.

Am I doing something stupid or are the clips wrong

 

[fr0sty]

Ahh OK I see now thanks

Edit: those noiseblocker fans look the business. Never heard of them, I use the bequiet one on the heatsink and 3 noctua 140mm. The noctua fans are louder than their rating. Great build quality etc but they are not 24db or whatever they are rated imo. I use the low noise adapter on them all and they can still go pretty loud.