Don’t worry, it is OK for me.
Perhaps it would have been better to put it in the thread I opened using play_raw (as this is more for filmic) after been adviced of opening it.
Help to improve skies using filmic and other modules. - Software / darktable - discuss.pixls.us
This kind of edit is what I was looking for: do as much as you can with filmic, but then use other module to expand hightlights and give light to the darks.
Using color balance and parametric masks does not give many times the effect I want: you cannot push light as much and it can create halos.