I figured there might be some interest in this so I'll post here.  I ran a league where 14 of the teams had the exact same players/lineups, and one of the things I wanted to test was the Pinch Hit and Stolen Base settings.  I didn't use a 0 setting at all (in my experience 0 means never), but here are the full season results for the teams that used the following settings:

Pinch hitting at-bats at the following settings:

5 – 210, 195, 188, 187
4 – 202, 196, 183
3 – 205, 187, 185
2 – 183, 175
1 – 171, 157

Stolen base attempts at the following settings:
(Note: This team had 747 real life stolen base attempts)
 
5 – 854, 839, 781, 779
4 – 792, 749, 710
3 – 699, 691, 655
2 – 506, 491
1 – 202, 177

The stolen base attempts make sense to me, but the PH totals seem to indicate it doesn't matter much which number you choose, as long as it's a number above 0.