Extentions_additional.conf modification

Hello

i have added some lines extentions_additional.conf in order to change behavior of [findmefollow-ringallv2].
to apply those changes i just reload asterisk “core reload” . i have to questions:

  1. i dont know how to do it extensions_custom.conf or extentions_override_freepbx.conf…i heard that its more safe.
    if someone knows please let me know
  2. on an old asterisk version i have added the script to add those lines on /etc/amportal.conf …in order this script to be run at every amportal restart …now amportal restart is depreciated…is there any workaround ?