I have blue hair, so I would immediately be marked out as a lefty. But hilariously enough one of the regulars in our local pub quiz has bright purple hair - not the subtle glassic rinse!) and is a massive Restore fan.
It's interesting about the mental maths - my DC used to come with me and help with the catering at our archery club, which involved making change, rapid calculation etc. That might well have been more useful than I was expecting.