In problem 7, what is the equity of vacating the 18 point to close within 9 pips? It would seem to me that the race is close enough that if green is playing for good breaks, one of the good breaks would simply be that green would outrace white.
Other than getting an immediate shot with 6-1,6-2,6-3 and 6-4, green risks pip wastage he cannot afford and is favored to surrender the first shot, as well.
Walter wrote a really nice article, as usual, with clear explanations and well-chosen comparison positions.