In my experience, cooling the underside of an SSD is all about slapping on the thickest thermal pad that the mobo allows. The top side cooler does a decent job of sucking away the heat, if it's large enough.
I would love to have such a capable cooler for the SoC in my mini PC. My, what crazy times we live in!
If you need replacement heatsinks for a N100, like I did, definitely look at old northbridge/VGA coolers, 1U server CPU heatsinks, and mosfet heatsinks.
If the heatsink mounting holes are non-standard length, you can use a slotted flat metal repair bracket, some washers, and longer screws (usually M2 or M3) to mount it.
I had an old Thermalright HR-05 with most of the hardware needed for completely passive cooling.