They're not "fine-tuned" in the slightest; they're cargo cult options that are going to give worse results on a compression-per-speed basis than the presets that already come with x264. Many of those options are completely redundant; they're specifying things that are already default!

There are quite literally dozens of scam companies built off x264, claiming in many cases that they made an "incredible" magical proprietary encoder with "revolutionary" compression. Of course they just run x264.

Fortunately it is extremely easy to identify an x264-encoded stream, even if all the headers are stripped and rewritten: it would be extremely difficult to modify x264 to cloak such a stream entirely unless you knew the code line for line, and even then, some of the features of x264 that are responsible for much of its compression advantage are extremely obvious in an analyzer (variance adaptive quantization).