The Moto-Guzzi Nuovo Falcone VOC

Yes, I've been a bit tardy of late. There's so little traffic on here I don't check every day.
I'm sorry, but I don't have any knowledge of how to wire with relay and stock regulator, but if others have practical experience of that, then as you say, it would be a far cheaper solution.
Smaller pully makes sense of course. I suspect my memory, as is so often the case these days, has let me down!