Within the last few weeks, there have been quite a few posts on this site about early game positions where it is right to slot and split (violating Magriel's advice), duplicating your opponent's numbers.
Also, Nack recently wrote a brilliant post about going to the 18pt, stating that the more builders your opponent has aimed at his 7pt, the righter it is to split there.
Check out the third roll positions 61P-33B-41 and 61P-33B-61 below:
         
    
         
 |  is Player 2
score: 0
pip: 155 | Money session
Jacoby Beaver | pip: 160
score: 0
 is Player 1 |
|
| XGID=----b-EBB---cD-b-c-e----B-:0:0:1:41:0:0:3:0:10 |
| to play 41 |
| 1. | 4 ply | 24/20 6/5 | eq: -0.215 |
| Player:
Opponent: | 44.92% (G:9.44% B:0.32%)
55.08% (G:14.50% B:0.61%) | |
|
| 2. | 4 ply | 24/23 24/20 | eq: -0.253 (-0.038) |
| Player:
Opponent: | 43.89% (G:7.85% B:0.23%)
56.11% (G:13.42% B:0.40%) | |
|
| 3. | 4 ply | 13/8 | eq: -0.294 (-0.079) |
| Player:
Opponent: | 42.77% (G:7.94% B:0.23%)
57.23% (G:14.99% B:0.53%) | |
|
| 4. | 4 ply | 13/9 6/5 | eq: -0.296 (-0.080) |
| Player:
Opponent: | 42.71% (G:9.54% B:0.33%)
57.29% (G:16.23% B:1.00%) | |
|
| 5. | 4 ply | 24/23 13/9 | eq: -0.317 (-0.101) |
| Player:
Opponent: | 41.82% (G:8.59% B:0.26%)
58.18% (G:15.21% B:0.63%) | |
|
eXtreme Gammon Version: 1.20
| is Player 2
score: 0
pip: 155 | Money session
Jacoby Beaver | pip: 160
score: 0
is Player 1 |
|
| XGID=----b-EBB---cD-b-c-e----B-:0:0:1:61:0:0:3:0:10 |
| to play 61 |
| 1. | 4 ply | 24/18 6/5 | eq: -0.170 |
| Player:
Opponent: | 46.14% (G:8.92% B:0.32%)
53.86% (G:13.81% B:0.60%) | |
|
| 2. | 4 ply | 13/7 6/5 | eq: -0.221 (-0.051) |
| Player:
Opponent: | 44.46% (G:9.36% B:0.30%)
55.54% (G:14.46% B:0.63%) | |
|
| 3. | 4 ply | 24/23 24/18 | eq: -0.222 (-0.052) |
| Player:
Opponent: | 44.71% (G:8.04% B:0.25%)
55.29% (G:14.15% B:0.43%) | |
|
| 4. | 4 ply | 24/23 13/7 | eq: -0.249 (-0.080) |
| Player:
Opponent: | 43.84% (G:8.10% B:0.23%)
56.16% (G:14.25% B:0.46%) | |
|
| 5. | 4 ply | 13/6 | eq: -0.351 (-0.182) |
| Player:
Opponent: | 41.30% (G:7.94% B:0.22%)
58.70% (G:15.74% B:0.59%) | |
|
eXtreme Gammon Version: 1.20
I rolled these two positions out on Jellyfish about twelve years ago, back when I could find no one else who cared about third roll positions.
Returning to the original position,
    
 
| is Player 2
score: 0
pip: 142 | | 7 point match | pip: 136
score: 0
is Player 1 |
|
| XGID=--a---EBCB--bBaabc-e----A-:0:0:1:61:0:0:0:7:10 |
| to play 61 |
eXtreme Gammon Version: 1.20
I see similarities between it and the two third roll positions.
Instead of duping 1s, you can dupe 3s by playing W (24/18 6/5). ALL 3s are duped, including 21 and 11. Even 53 is duped. If he hits you only on the 18pt, then you usually have 22 numbers from the roof that cover your 5pt and make a five-prime. Also, double 2s covers but makes only a four-prime.
You're gonna leave a shot anyway (unless you play the distributionally sick 8/7/1), so play the number so that you stand to get something good out of it.