I've finally had it with the femsatronic and ordered the vespatronic. I really really wanted to keep the stock flywheel but also want to ride the bike. so it goes.
In preparation I've gathered diagrams from:
'74 US Rally coversion to AC only
1974 Rally 200 - Batteryless but still 6V?
For more than 30 years I have lived in fear of 1974 US market Vespa wiring, but it's not actually that bad and I don't see the conversion being that hard at all. The most confusing part is that there are 3 different wires that head out from the battery/rectifier. One powers the headlight, taillight, and speedo bulb, the second powers the turn signals, and the third powers the horn and brakelight. But even though they come from different positions they are all powered from the battery.
OK, next figure out the Vespatronic.