Two balk questions

[Paul L]

1. When does a pitcher in the set position commit to delivering to the batter? One might think that lifting the free foot or separating hands could be a "motion naturally associated with his pitch", thus requiring pitching to the batter, but then no pickoff attempts could ever be made. So what do you look for in deciding when the pitcher is committed to delivering the pitch to the batter, e.g., after a pitcher in the set position raises the free foot?

2. How far does the pivot foot in the set position have to move backward in order to successfully step off? An inch? Partially over the back edge of the rubber? More than half a shoe width past the back edge? All the way back with no contact between pivot shoe and rubber? I'm thinking feints or overthrows to first.