"The 2 cube gammon value is .48 so that brings the minimum doubling point down to ~52.4%. It's actually a shade lower than this since a gammon by the leader with the cube centered will cost you the match."
It can go down much more due to removing all of the opponent's cube power. For example in the below position the gammon by the leader effect does not apply so if you knew the win percentages and gammon percentage you would have said not even in the window, (54.95 + .48 *2.73 = 56.24 < 58). However this is a double. It is even far from the last roll situation that is often needed to make a double correct when barely in the window. The opponent never gets an immediate cash and only a cube after 31, 41, or 51.
If the unnatural born off checker is bothersome the same point can be made in a modified position with it on the board. I had it borne off to stress there is more going on than opponent's gammons possibly lowering the window.
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| XGID=--BBBBBB------a-Bca-bbbbb-:0:0:1:00:0:1:0:3:10 | |||||
| Blue on roll, cube action? | |||||
| Analyzed in Rollout | No double | Double/Take |
| Player Winning Chances: | 54.80% (G:2.98% B:0.03%) | 54.95% (G:2.73% B:0.05%) |
| Opponent Winning Chances: | 45.20% (G:0.00% B:0.00%) | 45.05% (G:0.00% B:0.00%) |
| Cubeless Equities | +0.139 | +0.051 |
| Cubeful Equities | ||
| No double: | +0.034 (-0.017) | ±0.003 (+0.031..+0.037) |
| Double/Take: | +0.051 | ±0.003 (+0.047..+0.054) |
| Double/Pass: | +1.000 (+0.949) | |
| Best Cube action: Double / Take | ||
| Rollout details | ||
| 5184 Games rolled with Variance Reduction. Moves: 3-ply, cube decisions: XG Roller | ||
| Double Decision confidence: | 100.0% | |
| Take Decision confidence: | 100.0% | |
| Duration: 3 minutes 20 seconds | ||
eXtreme Gammon Version: 2.10, MET: Kazaross XG2