Well, I would always defer to local methods, which is why I asked how many brood boxes. I get your point though, and I looked up some numbers.
I didn't think that the Italian box is double Lang depth. I believe that the Italians also use a Dadant variant (like the French), which uses brood frames around 300 mm (just under 12 inches) tall. For comparison, the Langstroth is 243 mm tall. So the Dadant-Blatt frames have about 20% more space than Langstroths. So your point is valid, he may not need double brood boxes, but I would definitely follow what the locals do in any case.
One more thought, Orvieto is on a bluff about 1,000 ft above sea level. The winters may get a little chilly, which might be a good reason for double brood or brood and a half.