I only know that the previous owner of my Series 4a did install a heated screen kit in my car. Right now I have no access to the car and I haven't tested this device, but I can't imagine that the PO installed this kit without having any success with it. How did things go on with uprating your alternator and especcially in combination with the 35 Amp gauge?
We ended up getting an 80amp WASP alternator and a voltmeter.. also a WASP geared starter motor..
have yet to fit these due to cold weather (unheated garage)and too many calls on our time at the moment.. although we are retired.. we seem to be busier than ever..