Scud, your probably a better mechanic that me but I'll throw out a little advice anyway.
have you added a ground wire from the reg to block? I don't remember about my V11 but the Tonti bikes mount the reg (and ground) through captured nuts in a bracket, not the best idea for constant ground supply.
white face Veglia tach? I seem to remember a dodgy ground connection inside the tach cover too..
your battery sounds good but tach failure was the first indication when my bike died on a trip.. turned out the regulator was not charging. I was a dummy then, got a new battery and rode toward home .. after another 60 miles the new battery was dead.. by then it was time to put Mrs fotoguzzi in a cab to get her home.