would take literally seconds to set up and a couple minutes to export using mkvtoolnix. just select target file size (eg, 100mb - most likely for host sites) or duration of each part then click 'start muxing'. done.
for an 11gb 1080p h264 .mkv it takes less than 5 minutes on a mediocre core i5 system.
would only take a moron hours to do.