[Remops] hod.aarg.net nym question

[Fritz Wuehler]

What are the restrictions on PGP/GPG keys for setting up a
hod.aarg.net nym?

Can I used gnupg instead of pgp?
Is the default gnupg key key type OK?
Are 4096 bit keys OK?

Also, what about changing the key details but keeping the same key-ID,
such as revoking and adding subkeys and changing the expiration date?
How do I update the key on hod.aarg.net?