[Retros] File-filling proof games

[Noam Elkies]

Has anybody tried to shorten my file-filling proof games?
My records were 6.5 moves for the f-file, 8.5 for the d-file,
and 8.0 for all other files, mostly symmetrical; but it turns out
that an asymmetrical 7.5 exists for the a-file (C+ Popeye, 1 sec.):

Stipulation dia7.5
Pieces  White  Ra1 Sa3 Ba5 Qa2 Ke1 Ba6 Sg1 Rh1 Pb2 Pc2 Pd3 Pe4 Pf2 Pg2 Ph2
        Black  Ra8 Sa7 Bc8 Qa4 Ke8 Bf8 Sg8 Rh8 Pb7 Pc5 Pd7 Pe7 Pf7 Pg7 Ph7
+---a---b---c---d---e---f---g---h---+

|                                   |

8  -R   .  -B   .  -K  -B  -S  -R   8

|                                   |

7  -S  -P   .  -P  -P  -P  -P  -P   7

|                                   |

6   B   .   .   .   .   .   .   .   6

|                                   |

5   B   .  -P   .   .   .   .   .   5

|                                   |

4  -Q   .   .   .   P   .   .   .   4

|                                   |

3   S   .   .   P   .   .   .   .   3

|                                   |

2   Q   P   P   .   .   P   P   P   2

|                                   |

1   R   .   .   .   K   .   S   R   1

|                                   |

+---a---b---c---d---e---f---g---h---+
  dia7.5                    15 + 15

Perhaps some file than f can be filled in a Shorty proof game
(7.0 moves or fewer)?

NDE