Sorry I missed your question earlier!
We set the timing electrically here at the factory using some pretty sophisticated equipment... to set it exactly where we set it would require more than what I'm sure you have in your pit!
BUT... I can give you a pretty good appoximation of where your timing should be set:
If you notice that there are slots in the timing ring on either side of the solder tabs on the motor... the timing ring only has a fixed amount of adjustment in either direction... in either direction you will notice that at it's maximum the slot will just tuck up against(or sometimes just behind) the solder tabs.
When looking at the back of the motor fully advanced would be the slot on the right being behind/next to the tabs on the right side... fully retarded would be the slot on the left being behind/next to the tabs on the left side.
The stock timing is just a bit lower than half way... so I would just set it to the middle and back it off a milimeter or two and go from there.
Sorry I cannot be more precise but I could give you readings that we look for here...but they wouldn't mean anything do you without the same setup we have here!