Well who need mounts? I find cable ties work great... when done this way.
8 cable-ties, along with some small nylon washers, and sticky back foam like say the thin sound insulation backing. Now I don't loop them, I thread a washer on the cable-tie; then slip that though the fin(s) in 4 places for the fan size I've chosen. Cut 4 little foam insulator pads and affix them over each screw holes on the fan to space and isolate the fan and fins. Position the fan over the 4 tie’s coming through the fins and again use the washers and ratchet block from the 4 other tie’s to tighten the fan in place. Finally trim all the ends and you have very clean, tight, mounting that doesn’t ruin the heat sink. Been doing it like that for years.