I'm the author - I didn't pick duplicates as the main suggestion partly because it's not clear if all TLS servers will accept that, but also because it's trivia

I'm the author - I didn't pick duplicates as the main suggestion partly because it's not clear if all TLS servers will accept that, but also because it's trivial for TLS fingerprinters to detect and defeat that automatically if they chose too. They just need to always strip subsequent duplicates from the cipher list before hashing, and the whole technique becomes useless. I doubt that's happening today, but I suspect it will very quickly if duplicate ciphers become commonplace. Actually reordering ciphers meanwhile definitively changes the hash, so there's nothing they can do in the general case at least, and there's a reasonably large number of acceptable non-duplicate orderings available to choose from. Duplicating ciphers is a good technique that's definitely worth investigating too, but it has its limitations, and it's not a silver bullet.