Marcel, glad it helped you (that was the purpose of the tutorial), have you as well tried using WinCache? as it has been recently updated for PHP 7, so in terms of static page loading OpCache works well, when server comes under load its there when WinCache shines.
and regarding use of OpCache, by the time I created that tutorial OpCache wasn't taken as much seriously as it should be despite moodle recommending it and as well PHP developers tweaking it specifically for moodle, now MOST of the shared hosting are as well turning their OpCache on for multitude of reasons.
Thanks for adding to IPV6 issue, not that I have experienced any, but then I am not using it in a production environment yet (soon to be) for me to revise tutorial will all sorts of tweaks possible.