Yeah, that is the problem with the JL manual.
We tried to look it up when I first worked on the bike of Milton, but failed as well.

Earlier versions of TP sensors have slotted holes, so you can twist the sensor before bolting down.
This is the principle I used (I elonginated the holes for this) on Milton's bike to re-adjust the sensor, so "enriching" the mixture.

However, as the sensor is originally fixed, it should indeed be a setting procedure, either internally (something like you describe), or by means of the external diagnosis software.
Perhaps Milton can chime in with his factory contact?

The voltage story is right, bad batteries can cause strange problems. But you can easily check it with a multimeter:
- check voltage of battery on dead engine
- check voltage of battery on dead engine, with all lights and other consumers on
- check voltage of battery on dead engine, with all consumers on, trying to start it
- check voltage of battery on running engine, at 2.000, 3.000 and 5.000 rpm
Let me know the figures and I will tell you if they are ok.

Eric