G'day Bondy,
Important! I just went out and checked on my machine. The White wire with the 'shield' is NOT a magneto wire!! Looks like it is another alternator output ( AC for headlight from what I just measured). Remove this from the ignition switch and secure it so it can't short to ground. Do the same with the other alternator output as well if you aren't wiring it in for the moment. Don't let them short as it may damage the alternator.
I can't see a loose magneto connection on my machine for use by the end user. I wouldn't worry about it for now (or ever?) as you can shut it off with the magneto ground provided on the throttle lever once it's rigged correctly. If you want to put it through the ignition switch we can deal with that later.
I'd be securing the solenoid to the can before power-up too.
Sorry again for the bum steer.