Thank you - I will try it this way.
Grateful to have a vacuum gauge since few weeks.

The engine has now power issues. It reaches 100 kph within factory specs and also achieves top speed of 190 kph (Yes- we can do that in Germany :-) ).

If nobody can help me with the spring issue during the weekend I will contact the superior kit manufacturer and ask them for clarification.
Of course I will share the result here later on.