With such a big pip count lead white should double. Should black take? I think this comes down to timing. Will black get a shot before black's board crunches and how likely is it that black would loose a gammon if black doesn't hit. With nine outfield crossovers I think black's timing should hold up. Will white leave a shot? Maybe 50% of the time. Will black hit it? maybe 30% or the time. I think black would have a good chance of containing the checker but still might escape and win a few games. Will black be gammoned, lets say 20% chance. So with 15% hitting chances and 20% chance of being gammoned I would pass. If white holds the cube or not a Jacoby game I would Redouble/Pass.

What about at 2a-7a. You just need to apply this to the match score. ATS, black's take point is 22% so it is a pass. Should white double? If white plays on she has 80% GWC of which 20% are doubles. If white doubles and black passes, black's MWC is 9%. I think it is close. If you give a gammon value of 50%, white's Equity is 80% + 10% = 90% so white is slightly better of doubling now. My rule of thumb though is to play on when I have reasonable gammon chances and I am 2 away.