Theorycrafting Demon Form and Going Beyond 10 Stacks

Howdy, folks. After some very disappointing revelations from testing some nodes, I am back to the drawling board.

Demonform was the main reason I picked Witch/Infernalist, as I love Risk/Reward Mechanics and attempting to build around mitigating Risk.

As it stands, Capping Demonflame at 10 with "Mastered Darkness" means 5% HP Loss/Second and is extremely manageable, even without any node buffs/specific gear/Vitality Gem.

However, I want to go beyond 10, and have a way that Demonform can be entered and sustained for a longer period of time, since more stacks equals more goodies. It needs not be infinite, but the longer stayed in the form the better.

Here are some overview bits for y'all:

• Demon Form grants the following:
  • Shapeshift Form (Loses Weapons)
  • +25% Cast Speed
  • +6 Level to All Spells
  • Gain 1 Stack of "Demonflame" per Second
  • Lose 0.5% of (Max) Life per Second per Demonflame
  • Deal 18% increased Spell Damage per Demonflame
• You can be a baby like me, and take "Mastered Darkness", which caps Demonflame at 10, meaning 5% Life lost per second and 180% Spell Damage. Respectable, but we want to go beyond.
• Chaos Inoculation (CI) will not benefit us at all. Demonform Kicks you out when you hit 1 Life, and since CI has you always set to 1 Maximum Life, you cannot enter Demonform at all.
• Mind over Matter (MoM) will not benefit us at all. Demonform uses the keyword "Lose" as opposed to Take or something similar, meaning that the Life Drain happens DIRECTLY to Life, and will not apply to Mana first.
• To that end, Eldritch Battery (EB) will not work either, since we are not worried about bolstering our Mana to counter the "Life Loss". Also upsetting Side Note: EB apparently only cares about Base Energy Shield, not what it is after Modifiers.
• Since Demon Form is a Shapeshift, and we lose our weapons, we lose our main source of Spirit, our Scepter. Generally this means we lose our Minions, but also means that we lose access to some Spirit Gems or Support gems like Vitality/Clarity. This can be worked around, but operate under the assumption that we have a max of 120 Spirit from Campaign Buffs. Gear can provide additional Spirit, but let's ignore Gear for right now and just focus on the Node Baseline.
• The only Gear I can say a hard yes too is Ghostwrithe, to convert X% of Life to ES, reducing the Impact of Demonflame substantially.

To that end:

• Is it worth dipping over to take the 1.1% Life Regen bonus from "Resiliant Soul" and the 3 nodes around it? That only Mitigates 2 Stacks at that point.
• I am making this with the incoming Summon Raging Spirits (SRS) Nerf in mind - going from 10 max spirits down to 5. Minions being unsummoned during Demon Form is fine, SRS still will contribute a good deal of damage even with only 5 present, just will not be the main source since we're going to focus on our spells.
• While SRS would be beneficial for Fire, would another Element for Infernalist be better? Ice or Lightning? I hear good things about Ice.
• Pyromantic Pact replaced your Mana with Infernal Flame, and builds up instead of drains. Many people have said that this is bad, and I kinda agree - but a big benefit of it is that you have a constant 10% Regen Rate on Infernal Flame after not casting for 2 seconds, and you can then ignore any Mana Regeneration Nodes and build towards other stuff. Worth or not?

Any input would be beneficial!