This position could be a poster child for the contrast between modern BG theory and Magriel's old dicta of "don't slot while split" and "don't come under the gun."
I don't plan to post Nack's variants (I'll leave him to do that if he wants) but I'm posting a few other positions below which can be analyzed using similar principles. They all feature a builder on White's 9pt. I'll leave the retroanalysis and nactation to those who like that sort of thing.
  White is Player 2
score: 0 pip: 160  Unlimited Game  pip: 168 score: 0
Blue is Player 1  
XGID=bECcEaaceAA:0:0:1:51:0:0:0:0:10 
Blue to play 51 
1.  Rollout^{1}  Bar/20 6/5  eq: 0.231 
 Player: Opponent:  45.74% (G:11.87% B:0.63%) 54.26% (G:19.77% B:1.13%)  Conf.: ± 0.015 (0.246...0.217)  [100.0%] Duration: 29 minutes 35 seconds 

2.  Rollout^{1}  Bar/24 13/8  eq: 0.297 (0.066) 
 Player: Opponent:  43.58% (G:11.83% B:0.66%) 56.42% (G:19.08% B:1.00%)  Conf.: ± 0.014 (0.311...0.283)  [0.0%] Duration: 26 minutes 20 seconds 

3.  Rollout^{1}  Bar/20 24/23  eq: 0.308 (0.077) 
 Player: Opponent:  43.81% (G:10.63% B:0.53%) 56.19% (G:18.62% B:0.67%)  Conf.: ± 0.016 (0.324...0.292)  [0.0%] Duration: 27 minutes 17 seconds 


^{1} 1296 Games rolled with Variance Reduction. Dice Seed: 271828 Moves: 3ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10
This one's a similar but somewhat tougher decision since White has a more threatening attack and 13/10 is more flexible than 13/8. W gets you gammoned significantly more often. This could stand a longer rollout but I'm not planning to do one.
  White is Player 2
score: 0 pip: 151  Unlimited Game  pip: 168 score: 0
Blue is Player 1  
XGID=bECbEacbeAA:0:0:1:31:0:0:0:0:10 
Blue to play 31 
1.  Rollout^{1}  Bar/22 6/5  eq: 0.442 
 Player: Opponent:  41.48% (G:10.40% B:0.49%) 58.52% (G:24.67% B:1.29%)  Conf.: ± 0.016 (0.458...0.427)  [99.6%] Duration: 26 minutes 04 seconds 

2.  Rollout^{1}  Bar/24 13/10  eq: 0.472 (0.030) 
 Player: Opponent:  39.57% (G:10.39% B:0.49%) 60.43% (G:20.23% B:1.52%)  Conf.: ± 0.015 (0.487...0.457)  [0.4%] Duration: 26 minutes 07 seconds 


^{1} 1296 Games rolled with Variance Reduction. Dice Seed: 271828 Moves: 3ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10
This one was surprising to me since Blue is ahead in the race and has a slightly weaker board. And actually, 24/20 24/23 is very close.
  White is Player 2
score: 0 pip: 152  Unlimited Game  pip: 147 score: 0
Blue is Player 1  
XGID=bBECcCacdbB:0:0:1:41:0:0:0:0:10 
Blue to play 41 
1.  Rollout^{1}  24/20 6/5  eq: 0.264 
 Player: Opponent:  44.12% (G:15.03% B:1.20%) 55.88% (G:22.17% B:1.26%)  Conf.: ± 0.007 (0.271...0.257)  [99.3%] Duration: 1 hour 17 minutes 

2.  Rollout^{1}  24/23 24/20  eq: 0.277 (0.013) 
 Player: Opponent:  43.74% (G:14.27% B:1.15%) 56.26% (G:20.96% B:0.78%)  Conf.: ± 0.008 (0.285...0.270)  [0.7%] Duration: 1 hour 16 minutes 

3.  Rollout^{2}  24/23 13/9  eq: 0.317 (0.053) 
 Player: Opponent:  42.81% (G:14.09% B:0.98%) 57.19% (G:21.21% B:1.11%)  Conf.: ± 0.015 (0.332...0.302)  [0.0%] Duration: 19 minutes 05 seconds 

4.  Rollout^{2}  13/9 6/5  eq: 0.319 (0.055) 
 Player: Opponent:  43.00% (G:14.84% B:1.07%) 57.00% (G:20.67% B:1.72%)  Conf.: ± 0.015 (0.334...0.304)  [0.0%] Duration: 20 minutes 20 seconds 


^{1} 5184 Games rolled with Variance Reduction. Dice Seed: 271828 Moves: 3ply, cube decisions: XG Roller
^{2} 1296 Games rolled with Variance Reduction. Dice Seed: 271828 Moves: 3ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10
Somewhat similar to the previous position but an easier decision, since White's attacking potential is reduced relative to her priming potential.
  White is Player 2
score: 0 pip: 153  Unlimited Game  pip: 147 score: 0
Blue is Player 1  
XGID=bBECbCaabbeB:0:0:1:21:0:0:0:0:10 
Blue to play 21 
1.  Rollout^{1}  24/22 6/5  eq: 0.179 
 Player: Opponent:  45.82% (G:15.32% B:1.09%) 54.18% (G:19.56% B:1.06%)  Conf.: ± 0.016 (0.195...0.163)  [100.0%] Duration: 22 minutes 14 seconds 

2.  Rollout^{1}  13/11 6/5  eq: 0.231 (0.052) 
 Player: Opponent:  44.18% (G:15.37% B:1.25%) 55.82% (G:18.94% B:1.27%)  Conf.: ± 0.019 (0.250...0.213)  [0.0%] Duration: 20 minutes 50 seconds 

3.  Rollout^{1}  24/23 24/22  eq: 0.246 (0.068) 
 Player: Opponent:  43.96% (G:14.23% B:0.88%) 56.04% (G:19.10% B:0.82%)  Conf.: ± 0.016 (0.262...0.231)  [0.0%] Duration: 20 minutes 22 seconds 

4.  Rollout^{1}  24/21  eq: 0.265 (0.086) 
 Player: Opponent:  43.59% (G:13.97% B:0.95%) 56.41% (G:19.68% B:0.82%)  Conf.: ± 0.015 (0.280...0.250)  [0.0%] Duration: 20 minutes 12 seconds 

5.  Rollout^{1}  24/23 13/11  eq: 0.298 (0.119) 
 Player: Opponent:  42.67% (G:14.63% B:0.94%) 57.33% (G:19.58% B:1.03%)  Conf.: ± 0.017 (0.315...0.280)  [0.0%] Duration: 20 minutes 15 seconds 


^{1} 1296 Games rolled with Variance Reduction. Dice Seed: 271828 Moves: 3ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10