Nick,
Your LD(39,6,2,2)=55 wheel still has 8 uncovered pairs.
They are:
3 9
3 22
5 38
9 34
11 36
16 23
23 35
31 35
Using your wheel and Covermaster
LD(39,6,2,2)=57 can be created:
1 2 3 4 5 6
1 7 8 9 10 11
1 12 13 14 15 16
1 12 17 18 19 20
1 13 21 22 23 24
1 25 26 27 28 29
1 30 31 32 33 34
1 35 36 37 38 39
2 3 14 17 25 30
2 4 7 18 21 35
2 7 16 24 28 33
2 8 15 19 26 31
2 9 13 21 27 36
2 10 11 12 22 37
2 10 23 27 32 38
2 13 20 29 34 39
3 4 8 23 29 36
3 5 7 21 31 37
3 7 12 26 32 39
3 10 13 18 26 33
3 11 15 28 30 35
3 11 19 24 34 38
3 16 20 24 27 31
4 5 12 15 27 34
4 8 16 20 33 38
4 9 17 24 26 37
4 10 13 19 28 38
4 10 14 22 31 39
4 11 16 25 30 32
5 8 13 17 32 35
5 9 16 18 28 39
5 10 24 29 30 35
5 11 14 20 23 26
5 19 22 25 33 36
6 7 14 19 27 35
6 8 12 24 25 39
6 9 20 22 28 32
6 10 16 17 34 36
6 11 13 18 29 31
6 12 21 26 30 38
6 15 23 25 33 37
7 13 20 30 36 37
7 15 17 22 29 38
7 18 23 25 34 38
8 14 21 28 34 37
8 18 22 27 30 37
9 12 14 29 33 35
9 13 14 25 31 38
9 15 19 23 30 39
10 15 20 21 25 35
11 17 21 27 33 39
12 17 23 28 31 36
14 15 18 24 32 36
16 19 21 29 32 37
16 22 26 34 35 36
3 5 9 22 34 38
11 16 23 31 35 36