Regarding colours of the Italian torpedoes i recieved the following answer from an expert on the field:
"Italian torpedoes were left in natural metal overall, and were greased with oil in order to prevent corrosion. Detachable wooden tail was painted light grey. Silurificio Italiano's built examples had a cap that was usually a light colour, probably the grey as above, but perhaps also the same light blue of propeller blades. Sometimes they appeared dark, like standard Italian Dark Olive Green, or possibly a dark blue used for Italian bombs"
Here is a link to their colourguide to planes, ships and their crews:
http://www.stormomagazine.com/RegiaA...sinWWII_3a.htm