Great guide, thanks. I also skipped the steps 6..9. The display could be lifted so far that I was able to insert a DVD case to keep it up.
I then replaced my WD hdd with a SEAGATE SSHD ST1000DX002 and shortend the temp sensor cable. As I thought it will reflect in the system as 0°C.
After 8h of restore from a USB2-external HDD the software SSD-Fancontrol showed me a temp reading of 47°C. Also after some hours of hibernation (sleep mode) the temp showed 22°C (room temp). So it seams to work.
How is that possible without the temp sensor cable connected to the disk?