Looks like applying thermal paste is a bit of a holly subject for many people. I did a search recently since I got 2 new 6core Xeon CPUs about this subject and I found something that is very usefull:
https://www.pugetsystems.com/labs/articles/Thermal-Paste-Application-Techniques-170/
You can see there several methods and the conclusion at the end with pictures! Good stuff.
Now that we have an actual coolant vessel this is an obsolete technology Attila! ;D ;D
Sorry for being old-school :D
But speaking seriously - until I did maintenance to my machine, I had no idea whatsoever that a magic like "thermal grease" even exist... The guys at the computer shop talked between one another saying "go ahead, and change a paste here" and I was like "deeeeerp?" :o :o
But you can really feel the difference.
I don't really understand some terminology behind it (break-in period?) but then again, as an end-user I don't think I have to.