PGP/GPG Multiple Keyring Synchronization Question

[Kevin Benko]

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NOTE:  I'm sending this to two lists, so some of you may be getting
duplicates.

BACKGROUND:

I'm in transition between PGP and GnuPG

I'm using:
PGP version 6.5.8 CKT build 08,
GnuPG version 1.2.1rc1-nr1 (nullify release),
GnuPG version 1.0.7-3

I'm running WIN98, and I've got CygWin version 1.3.13 installed.
PGP and GnuPG(1.2.1rc1-nr1) are installed under windows
GnuPG(1.0.7-3) is installed under CygWin

Because I'm in transition, I'm maintaining a separate keyring for
each of the three PGP/GPG programs, and I'm using either MS-DOG batch
files or BASH shellscripts to synchronize the keyrings.  The scripts
are set up such that each program handles exporting its own keyring
to a temporary file and importing the other programs' temporary files
into its own keyring.  I've also made absolutely certain that none of
this exporting/importing is done by two PGP/GPG programs at the same
time.

PROBLEM:

I haven't checked where this has occurred, but I've noted that I have
been accumulating multiple self-signatures under my default key.

That is, with regards to my default key, I noticed the self-signature
for that key keeps getting added to the other self signatures until I
have three or four self-signatures.  I can easily delete the
extraneous self-signatures, but this is still bugging me.

POSSIBLE SOLUTION:

Under what circumstances can all three PGP/GPG programs share the
same keyring files?

Under what circumstances should the three PGP/GPG programs *not*
share the same keyring files?

MORE INFO?

Would it be helpful for me to export the public key in question?  If
so, I can post a URL for the thing.

Thank you for your time.

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-- 
Kevin Benko

"The natural tendency of every government is to grow steadily worse--
 that is, to grow more satisfactory to those who constitute it and
 less satisfactory to those who support it."

-- H.L. Mencken