If they can MitM you to see your post, base64 will just draw more attention. Consider checking SSL fingerprints from trusted and untrusted locations instead.
I would also suggest browser addons that will alert you when SSL fingerprints change, but they don't work in FF any more, so you will have to do it manually understanding that they can swap out certs based on tcp packet size. You can also pin the cert, understanding you will have to update it if HN changes out their certs or they expire.
They cannot read HTTPS unless it is using TÜBİTAK certificate (all .gov.tr and some other .tr domains use this). There are more layers of censorship till central gateway, which is inferior to, but structurally more robust than GFWoC.
