Big step forward !!
First of all I wasn't quite enough accurate describing the 4 positions so here again, more specified:
1. not touching the bottom plate (on an acoustic set this is the position for playing fully open)
2. touching the bottom plate only by letting my foot rest relaxed on the pedal (on an acoustic set this is the position for playing half open)
3. increasing the pressure just a little bit by lifting my heel (on an acoustic set this is the position for playing closed)
4. actively applying some pressure using my leg (on an acoustic set this is the position for playing tightly closed)
I switched polarity of the high-hat control output (I didn't change the highlvl/lowlvl values). I still only get the 2 different vu meter positions (completely full and completely empty) / sounds (fully open and tightly closed) BUT now the switching from "vu full" to "vu empty" takes place already at position 3
I got a feeling we are approaching the wanted result. Now I assume we have to get ...
... the vu meter to being empty at position 4
... the vu meter to being 1/3 full at position 3
... the vu meter to being 2/3 full at position 2
... the vu meter to being completely full at position 1 (this is already the case)