Quote - That's what I meant by the need to tune it. If the ambience is high enough, you'll never detect that you are in shadow with that setup.

This is the same story as with my shadow catcher. Given enough IBL, there is no specific pre-defined level that means we're in a shadow. It has to be calibrated to detect a shadow in each situation. There will be times where there is so much IBL that the lowest value coming out of the Diffuse node is still more than 1/2.

i am happy that you didnt tell me. it was nice that i found it myself.