I'm still running single leading shoe drums on my '63 mk1. Braking is 'gradual' plenty of planning ahead required. Having said that it's generally pottering about at not much more than 50 mph. It's still got all its original features, narrow tail crank, coil spring clutch, dynamo, positive earth etc, I don't want to start modifying it although better brakes would be an asset.
How come you've stayed with positive earth?