Using GPG to Encrypt Your Data
For GPG symmetric encryption, the kind the article describes, here are the best options I've found for my typical case:   gpg --symmetric \
   --cipher-algo aes256 \
   --digest-algo sha256 \
   --cert-digest-algo sha256 \
   --compress-algo none -z 0 \
   --quiet --no-greeting \
   --no-use-agent "$@"

I keep this command here:    https://github.com/SixArm/gpg-encrypt

The options are chosen to balance tradeoffs of convenience, strength, and portability.