After advice from someone who's done it

[wiltshire builders]

I did a trip in 2013 to Italy crossing the stelvio pass (overrated) and coming back via the Mont blanc tunnel (horrendously expensive)
Did it in 11 days, including 3 days in mugello, averaging 250-300 miles a day. Our longest day was 450 miles.
Started in France and crossed into Belgium then down through Germany and the black forest.
Austria then crossed into Italy.
Best roads were the B500 in Germany and the San Bernardino pass.

[QB1]

Thanks Wiltshire Builders I was starting to get the impression some of the passes are a little over-rated and are just a long slog. The San Bernardino pass looks a super option.