Remux means stripping the additional audio and subtitles while keeping the video stream untouched and standard 4k disk comes from 66GB to 100 GB disk size. Most of the time I download the entire 4k disk and remux them before storing it in my hard drive. The average size depending on the movie most of the time becomes 40GB+ . 12to16GB files are encodes of those movies where data of both video and audio has compressed. I have experimented with small 4k movie files for example "Edge.of.Tomorrow.2014.2160p.WEBRip.DTS-HD.MA.7.1.x265-HDeX" 16GB because the disk is not out and it's one of my favorite movies. On my 55" tv the quality is passable maybe a little soft but no biggie.