Many thanks for your posts.

I am looking here for the correct removing tool since, as Mr. Laidlericon said, my homemade tool has broken the prongs!
I would ask about the warming procedure....I have the way to use an oxyacetylene torch not only the cheap gas burner but my fear is to damage the thermal treatment of the cocking piece.....for istance the trigger release surfaces....your opinions?
I realized now that the threads of the strikers are differents between No4 and No1.....is it right?