Guess it depends on when you plan on driving the speedster. CA is quite different than other states. We tend to have drastic changes from our daytime highs and nighttime lows, more so than other states. Here in the Bay Area, our summer highs are mid 90s, and our summer lows are mid 50s.
I've driven to many Cars and Coffee events at 5:30am where I was happy I had the slightest bit of heat pouring out to keep my legs warm. The addition of the full tonneau cover really worked magic in keeping the heat around my body.
The attached photo was taken going to a Cars and Coffee in November 2019. It was probably 45-degrees outside at 6:30am. @ericthered took the photo from his 550 Spyder. Guess who was happy they had a "top" and some heat?