The decision on where to take a pivot cone (that's what we call a single cone turn here in SoCal) depends on where the course goes after the pivot and what kind of car you're driving. If in your example above there was a long straight after the pivot then you are much better off maximizing corner exit speed. On the other hand, if there was another slow corner just after the pivot then you're better off extending the slalom stright by going fast into the pivot.
Other considerations:
1. Traction - if it looks like a first gear pivot then proper corner exit is much more important because traction wil be a problem.
2. Momentum - if your car is horsepower limited then carrying speed through the pivot is very important so a wider line maintaining your speed will usually result in a faster time.
