The heat sinks in the video were the size of the CPU die.
The heat sinks in the link, are about 4x larger.
The heat sinks I use, cover the CPU, RAM and all.
Passive heat sinks don't cool that well. Especially not those with the tape they're using.
I tested out the sticky heat sinks, vs identical heat sinks without sticky back, and using dual sided tape. And both had identical cooling results.
The best thing is to get a heat sink without sticky back, and mount it with thermal paste.
For as long as the unit is kept horizontal, the thermal paste will keep the sink in place.
Additionally, one can give very good cooling, by using a 12V case fan (120-140mm, in case you have multiple units), and run them at 5V, or run 5V fans at 3.3V. They offer cooling of more than 20-25C.