Defensive clipping

[OverAndBack]

This was the Play of the Day today:

Runner A1 breaks free beyond the neutral zone at midfield. A2 is running between A1 and saefty B1, who is gaining fast on both of them. As B1 nears A2 he blocks him from behind and below the waist in an attempt to get to A1 to make the tackle.



Ruling: This is clipping and is illegal. If the contact would have been from behind and above the waist, it would have been legal per rule 9.3.5b

I understand that much.

We don't know if runner A1 scored. Let's say he scored, do you enforce the penalty from the succeeding spot (the spot of the try? That doesn't seem like much of a penalty. Rule 2-40-10 says "The succeeding spot is where the ball would next be snapped or free kicked if a foul had not occurred.")?

If he didn't score, and was tackled at, say, B's 35, would you penalize from the spot of the foul (which we don't know, either) or the end of the run? Whichever was worse for B? Or would A have the choice of taking the result of the play if that would be more yardage than they could get penalizing B from the spot of the foul?