When we bought our first Morgan we did a tour of France, first day a few miles from our hotel the heavens opened. Like DaveW I asked Mrs A do we stop or carry on - we carried on, she baled out at the hotel whilst I unloaded, the concierge just looked at me in bewilderment and didn’t offer an umbrella!
Later in the trip we were caught in a minor shower in town, even at 30mph we weren’t getting too wet until we came to a red light: by this time I’d acquired an umbrella which I unfurled causing a passing Frenchman to lose control of his pushbike.
To answer the question posed I avoid driving in anything more than a shower, where possible. I don’t think that the car has suffered from the occasional soaking but there’s no prizes for being the wettest driver and as others have said there are safety implications if like me you need glasses.
