Encoding movie with x265 feasible?

[-Habanero-]

I want to start using x265 for my Blu-ray rips but my main concern is the bitstream remaining intact for the coming years as x265 will continue to transform and change like x265. My very old x264 encodes from 2008 would sometimes corrupt/have seeking problems with decoders years later and this has been and on-and-off thing. The next ffdshow would screw it up, the next would fix it and the next would screw it up again. After 2009 is when all of my x264 encodes reliably playback.

So I'm worried this might happen with x265 as well or worse: it can't be decoded at all 5 years from now because it changed so drastically. How safe am I in this department?

Also, can anyone suggest some good settings to use? I've been doing blu-ray rips for years and years so I'm more than adept with x264 but x265 is completely alien to me. My strategy with x264 was to crank everything up for the best quality except settings that slow encoding down too much without real benefit (TESA, too high me-range etc.)
And of course some settings are changed for different content such as animation which are awarded more refs and slightly higher me-range. Is this all I would have to do with x265 as well? Add more refs for cartoons?

8 years ago I did this by testing everything out manually which I have no patience to do now because there is no GUI where I can easily change settings like x264vfw on vdub, there's no video editor that I can readily open the H265 MKV with and on top of that this encoder is really seriously slow that I end up zoning off somewhere else and forget about the test encode that finished an hour ago, then lose my train of thought.

[newpball]

Why not simply archive the blu-ray if you worry about those things?