Hi again.
Someone asked me via PM if I have been able to meintain my perfect alignment, and I thought this might be of interest, so I post this here. The answer is yes and no. I was now playing on 4 different days (including the day when I first had success) and it went like this:
1st day: win
2nd day: fail
3rd day: win
4th day: fail
What did I do on day 1 and 3 that I didn't do on day 2 and 4? Practice... I think it's mainly because of my head-turn-thing that it's difficult for me find the spot. When I'm there, it works as long as I play, and I can actually play a match without losing it (aim and match :lol

.
Day 5 will be a win, because I'm going to practice until I find it again.
I also noticed, that when I'm there, I don't care much about my arm anymore. Honestly I don't even know what my elbow does or if my upper arm is aligned properly, 90°... I don't care. I just force my cue to move on the "rail" that I perceive, and it feels good.
On the dark side, when I don't see the shots right ... well ... I don't want to play like that anymore. :barf:
It takes time and practice, I guess. Once you understand the concept and know how to find the spot, you are halfway there.