If you have no idea what "PHP_INI_PERDIR" or "PHP_INI_USER" are or how they relate to setting a .user.ini file, take a look at the ini.list page: http://www.php.net/manual/en/ini.list.php
Basically, anything in the "Changeable" column labeled as PHP_INI_SYSTEM can't be set in the .user.ini file (so quit trying). It can ONLY be set at the main php.ini level.