Need build advice. Channeling lightning spell, mana pool, shock

Trying to implement the idea of channeling build, faced with many questions that I have no answer due to little experience. Also asking for your advice, starting from the given conditions:

1. Channeling Physical+Lightning spell (Storm Burst / Divine Ire)

2. Selfcast
How to adopt channeling playstyle, for surviving in such hard game like PoE? I noticed, that my main problem over all time - I can't see when range damage can kills me because of much effects. I didn't dig into endgame, so I don't know much content. Maybe I can learn boss movements, animation, behaviour patterns etc, and compensate my "blindness", but with channeling I must stay on place, being a perfect target to land some ranged oneshot on me. I see solution with adding more movents between attack periods, but I need to start over again stacking channeling stages. So preferable develop tankiness.

3. Using Effect of Shock
Trying to build on "х% more dmg with hits per y% Effect of Shock". "Increased shock effect" does not raise effect beyond 50% cap, only make easier to apply minimum/ maximum values EoS with same damage. But there are sources "+x% Effect of Shock" which raise max EoS. Voltaxic Rift: +40%, Lightning Mastery "max EoS": +15% (wiki info differs however). Any other sources? Lightning Conduit also use EoS mechanic.

4. Witch Elementalist ascendancy for more EoS multiplier. Does build with some crits and decent endgame DPS still need raise EoS to easier apply max EoS (50% effect for 35% monster max life hit) on endgame bosses, or max EoS occurs easily when charecter come to endgame values of DPS?

5. Arcane Cloak. Needs big mana pool, minimum mana reservation. Should I leave mana pool fully untouched or I need 1-2 vital aura despite everything? How much % unreserved pool should I keep to maintain power of Arcane Cloak?

6. Mind over Matter. Fits well with big mana pool.

7. Pain Atunement (low life)
1) +Life Reserv
What put on reserv? How to manage reservation values and their cuts from support gems and tree to make life close to 30%?
2) +CI / high chaos res
Is it possible to make viable low life non-CI with chaos resistance? Is there instant chaos dmg in game that can pop low life charecter even with 75% chaos resistance?
2.1) If low life non-CI possibe: Should I cap to max chaos resist or I can stay at some point? How much chaos res is good in that case? Is it worth it to use Cleansed Thoughts (chaos res is doubled)?
2.2) If no instant chaos dmg in game can pop well resisted char: Is there any other mitigation or chaos avoidance mechanics which can be combinated to nullify danger from chaos dmg?

Up

I'd help OP but I don't really understand what you are asking there are many statements in here and not that many questions. Do you want a build suggestion for what ticks all these boxes or are you asking if these boxes are even necessary? I'll throw some out but have no idea if its what your looking for.

SB and DI are both viable, DI is vastly easier to play within the scope of the regular game due to clearing the area around you while you charge up/fire at the key monsters (rares etc). SB I personally think is a totem skill, its too much mouse work to use selfcast and you are too vulnerable while doing so.

Effect of shock is very easy if you are taking shaper of storms as an elementalist, you only need a bit over 200% to do capped now 65% shocks if you are using lightning damage and you aren't required to do it with your main damage skill so you need less due to access to ailment gems. You can prime a target with selfcast shock nova to do a 75% shock for example pretty cheaply in terms of gems.

Voltaxic rift is a piece of shit and i wouldn't even entertain using it, it has a unique mod with the shock scaling but the partial conversion to chaos guts every skill that can't access the other 40% ie everything aside from voltaxic burst and alternate quality spark. This is the definition of a unique with anti synergy.

due to shaper of storms crit or non crit is a personal choice, but crits always better because it always is.

Arcane cloak and MoM require you to leave your mana unreserved, you can use a blessing to get one aura for free of your choice and if you really want vit/clarity for watchers eyes you can then reserve those with life and leave them at level 1. You can get almost all of your shock effect from this however with 30% of your increased mana applying to shock effect as a lightning mastery.

If you want pain attunement you are looking at petrified blood, ivory tower hybrid (which works with MoM so is probably the right route) or coward's legacy. Personally ivory tower is the best SC choice.

Ivory tower makes chaos go to mana before life which handles needing too much of it however capping chaos resist is just a matter of efficiency on your gear, it can be done if you are willing to sacrifice dps for it but realistically you could get by with less.

2) Channeling skills are typically considered bad/unviable exactly because of the issue you are having. They need to stand still. POE is not designed to tolerate players standing still. Standing in one place for more than a second has a high chance of getting you killed so stutter stepping is vital.

Ways to solve this are only 2. Reduce the needed channel time as much as possible. If you can fully channel your spell in 0,5 seconds and release you are good. Everything beyond 1 second is bad. Details here depends on what spell you want to use.
The second option would be to make a really tanky build. However this comes with the downside of requiring significant investment and usually with a steep cost in form of less damage, all the more so for a new player like yourself who probably isn't swimming in currency. The only setting that can somewhat reliable stand still during mapping and channel a skill would be a max block build with high armor (at least 30k), Melding of the Flesh, capped Chaos Res and Aegis Aurora. That setting heavily mitigates any damage coming in and recovers your HP every time you block so it's fairly selfsustaining. You don't have to do anything to stay alive.

3) I am not aware of other sources, lightning conduit and other spells scaling directly from shock were introduced this league so it's still rather new.

4) This is a matter of currency at the end of the day. Since you are new you'd be better of planning for as much shock effect as you can since your DPS most likely won't be enough on it's own.

5, 6 and 7) If you want to use AC and MoM then you have 2 choices.
1. to just use 1 damage aura like wrath either using a blessing or the essence worm unique ring for free + maybe one absolute reservation aura like precision or clarity to keep as much mana open as possible.
2. Use the Ivory Tower unique armor. This armor gives you Energy Shield per life you have reserved and redirects all chaos damage to your mana pool. With this armor you can combine an open mana pool for AC and MoM with low life and pain attunement. With 50+ chaos res (easily achieved with Presence of Chayula amulet) you can easily stomach pretty much any chaos hit and chaos dot's are no problem as long as you have a mana flask. Since it's also energy shield based and has armor it would also work well with Aegis Aurora mentioned above so it might be worth a try. Probably can't have too high expectations for the damage with that setup though, it's only half the auras compared to typical shavrone low life builds and it will require max block + you'll be using a defensive amulet. Unless you can stack a ton of mana (8k upwards) you'll probably find yourself on the low end damage wise. Not to a point where endgame is impossible but you most likely won't oneshot map bosses.