Nearly 4,000 km and we only put the hood up when parked in a few places for a little extra security and for about 30 minutes when we encountered heavy rain on that parking lot known as the M25.
On the last night on the way home we encountered light rain between the Zurich and Bellinzona in Switzerland we left the hood down but it was not really pleasant driving even though no rain was coming in. We took the San Bernardino tunnel and encountered quite a few heavy vehicles. The glare of oncoming headlights on the wet screen was difficult to cope with.
It would be a spectacular road in daylight.
PS. Speaking of spectacular roads we tried the Schwarzwaldhochstrasse in the Black Forest. Not to be missed if driving in that part of the world.
http://en.wikipedia.org/wiki/Schwarzwaldhochstra%C3%9Fe