Yeah, I already scoured the Alitalia website; heck, I even have the printed terms and conditions of the MilleMiglia programme right here and I'm still none the wiser :-)
I don't understand how different airline rules interact in cases like this ... for example, Alitalia claim they'll give you double miles for Delta flights in C/J/F, whereas if you're in Delta SkyMiles you get 1.5x!
Also, Alitalia seem to credit me with full miles for travel on all sorts of weird and wonderful booking classes.