Order/changing of subkeys derogates compatibility!?

[gnupgpack]

After further investigation:

Actual version of 'Symantec Encryption Desktop 10.2.3' (former known as
PGP...) is supporting subkeys for signing or encryption in both directions,
accurate interaction with GPG-2.0.26/GPG-1.4.18. 

NOT working with subkeys for signing or encryption are:
PGP-6.5.1 / 6.5.1ckt
PGP-8.1 (thanks to Symantec support...)

I did try to get old version of PGP-9.0x, -9.5x, -10.0x, but it seems to be
impossible to get it even from Symantec enterprise support. Didn't find it
in download archives.
Maybe someone can help from private trial archive (email...)?

So finally there is still this open question:
How is the collaboration between actual branches of GPG-2.0/GPG-1.4 and PGP
versions:
9.0x
9.5x
10.0x?

Before generating new series of long term keysets, what do you think about
this keystructure:

Example-keystructure:
pub  4096R/97CA9679  erzeugt: 2014-11-22  verfällt: niemals     Aufruf: C
               Vertrauen: uneingeschränkt     Gültigkeit: uneingeschränkt
sub  4096R/9D22119A  erzeugt: 2014-11-22  verfällt: 2016-11-21  Aufruf: A
sub  4096R/884627F6  erzeugt: 2014-11-22  verfällt: 2016-11-21  Aufruf: E
sub  3072D/37F05D01  erzeugt: 2014-11-22  verfällt: 2016-11-21  Aufruf: S
[  unbek.] (1). vorname nachname (kommentar) <name at edu.com>

Thanks and regards, Chris