The movie was co-written and co-produced by Lidia Puglia, hairdresser on lots of SWs
The psychotropic sequence focused on a gigantic gold nugget, the speeded up barber shop scene that makes no sense at all, the 'beast in heat' dressed as a nun, a town called Trombstone (from trombare, to fuck), the mountain easily offended by bad language... Save yourself if you can!
For Mario Dani I checked the 1971 movie Los corsarios a.k.a. Pirates of the Green Island, and although without the mustache the actor who plays Marrison /Madison in Seven Nuns seems in.
Perhaps Carlos could check Bang Bang Kid (I don't have it) for final confirmation.
At this point Lello Pontecorvo could be Whisky Joe: I'll check Società a responsabilità molto limitata (1973) as soon as possible.