[Lucien Nunes]

It's not really flowing to ground, it's just passing through the chassis metalwork to the other end of the spark circuit, which is unavoidably already in contact with the chassis.

What kind of coil is that in the spark circuit, and what triggers the spark? And how is the helix drive synchronised with the watch under investigation? Sorry, but if you're going to show us rectifiers in unusual pieces of kit you're going to get questions!

Your dwg is correct but the doubler configuration is most self-explanatory when drawn thus;