>> "At the very least, GnuPG must be emerged. Many applications today have some sort of support for PGP, so having crypt as a USE flag is a good idea. When desiring an email client capable of using GnuPG any of the following options are well suited: "
s/PGP/OpenPGP

>> "but do not use a size larger than 2048 with DSA/ElGamal keys. 2048 is generally more than enough for normal email communication. "
Why?

>> "a public key to other users it is important t"
public keyblock

>> "Generating a revocation certificate"
gnupg 2.1 automatically create revocation cert in openpgp-revocs.d

>> "Sending keys to key servers"
gnupg 2.1 defaults to hkps://hkps.pool.sks-keyservers.net that will use TLS, no need to specify keyserver. Keyserver options part etc is not relevant for dirmngr, just remove it. It can use tor, see https://sks-keyservers.net for details on pool, if specifying a .onion address it should work automatically if tor is running

>> Using a GPG agent
gnupg 2.1 do all secret key operations in gpg-agent, it is not optional , it will auto-start for OpenPGP operations, use-agent is noop and the eval to start it is wrong

!! Description is missing the most important part c.f key management, validation of keys before using for verification or encryption operation