Just use eth insight. Then you can keep phoenix and shako and have fcr. Can even swap those fcr rings for mf rings or SOJ etc... sell Ebotd and get a pride for your might merc.
Don't knock insight until you try it. It's basically best in slot, especially considering affordability and it's not close.
Make sure to pump blood oath so you take less damage. Use Hex siphon and your health/mana problems are gone.
I have no torch no skill GCs on my single player warlock. Have never even come close to loosing more than half of my health. Can farm P8 tier 5 heralds all day very safe. Merc dies sometimes but that's it.
Insight isn't even top 5 weapons. no skills, dmg and crit not so important.
Arioc's is best.
then i would use mephisto's book, 2 skills 5 fc amulet. 85% DS with gores and 75 fcr.
hex siphon is useless too.
can farm p8 very safe stricly means nothing since the build is too strong atm.