Code:
1. 11/7 10/7 Eq.: +0,660
0,696 0,151 0,005 - 0,304 0,084 0,005 CL +0,459 CF +0,660
2. 11/7 6/3 Eq.: +0,543 ( -0,117)
0,651 0,099 0,003 - 0,349 0,096 0,008 CL +0,301 CF +0,543
3. 10/3 Eq.: +0,500 ( -0,160)
0,615 0,091 0,003 - 0,385 0,060 0,003 CL +0,262 CF +0,500
4. 6/3 5/1* Eq.: +0,481 ( -0,179)
0,621 0,116 0,005 - 0,379 0,105 0,008 CL +0,249 CF +0,481
Truncated cubeful rollout (depth 10) with var.redn.
145 games, Mersenne Twister dice gen. with seed 763581857 and quasi-random dice
Stop when std.errs. are small enough: ratio 0,1 (min. 144 games)
Play: world class 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 8 more moves within equity 0,16
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]
6/3 5/1* looks attractive to the blind eye. But if black doesn't throw a 3 as a first step to escape in the next few turns, his board will crumble. White should be allowed to throw, so that those back checkers will get some more space.
10/3 at least keeps white throwing, though 11/7 6/3 is better, because if white throws that 6, he has to send the checker to the bar, and black likely doesn't have to break up his board. If black throws a 3 next turn he will complete his prime instead of moving his back checker, and is favorite to get another white checker.
11/7 10/7 is best because if white hits he needs to throw 25 or 26, otherwise in most cases he will leave a blot + space at the other side of the board. A bonus is that black has now two numbers to complete his prime.