I'm going to make this easy for everyone who hasn't read the entire thread to find out where to farm.
The Biggest run cover the most areas with the possibility of dropping this ring:
#1. Set your quest to a Royal Audience. (most are doing from unexpected Allies but royal audience ads quite a few more Ring capable mobs)
#2. Follow the quest line and clear all areas/complete all quests killing everything and popping every chest barrel etc. Until you reach the Oasis.
#3. Clear the entire Oasis all events caves tombs etc, then descend into the Forgotten Ruins.
#4. Once you have cleared the ruins you are done. Repeat from #1.
#1. Select Unexpected Allies quest.
#2. Clear entire area
#3. Save Adria
#4. Repeat From #1
#1. Select A royal Audience.
#2. Do entire quest but do not go into the sewers at the end.
#3. Exit game
#4. Resume game*
#5. Repeat from #2
*Resuming the game after a proper exit, will start you at the sweet spot without having to reselect a quest when creating a new game.
*After initial set up this run takes about 30 seconds and is 100% ring dropping Mobs.
There are many other variations posted throughout this thread, including the Op's. The First Run I posted in this post covers all areas containing mobs that can drop the ring without dropping any other legendary ring Instead.
There have been reports of people finding it withing a few minutes. This is called extremely lucky. Expect to take however long it takes to find this ring. It will most likely test your endurance and drive you crazy. I personally have over 40 hours into this without the ring dropping and many other have reported close to the same. Remember RNG is RNG. No amount of MF gear or Valor stacks will guarantee success. Legendary drop rates are too low to be effected much if at all by these things.
Try not to forget that proper nutrition and hygiene are still very important aspects of maintaining ones survival and self respect.