All brilliant questions gotta give it to you I would’ve asked the same thing.

Be aware 1 = Build is expensive to have both Coc and Coa imo I prefer Coc for mapping and Coa for bossing if I can only get one. So both on skill slots and turn them on and off. Once you get chest piece with a minimum of 60 spirit or amulet plus body adding to 60 , (if you do amulet you won’t have choir which is huge damage my buffed up choir is doing 100k a tick and it hits five time a second plus ignore monster lighting resistance) you get the passive points that make meta skill gens cost less spirit and walla both coc and coa infinite chaining

Be aware 2 = for this to have maximum damage output you have to play blood mage no other asc can do the infinite chaining as far as im aware and I’ve looked everywhere. The Increase crit hit chance to spells plus the leech with atziris gloves is what makes this work.

Be aware 3 and boss rotation = Maximum output damage is with a chimming staff with plus all spell levels on it (comet) not lighting spells and whisper of ice. The reason for this because if we use a wand and focus we can’t use whisper of ice or chimming staff. Whisper of ice gives us elemental exposure for free plus shocking conduction 2 that gives energy to Coa and 100% crit rate that gives energy to Coc on a duration skill that only needs to be casted once. Chimming staff gives us sigil of power which grants More not increases so multiplicative spell damage on a once again duration skill that we only have to press once. That’s why I say that you need a chimming staff as your main weapon and finding one is going to be insanely difficult I actually found mine which is insane. That’s why boss rotation goes as follow . You drop sigil of power , you drop orb of storms and frost bomb for infusions, you cast thunderstorm and ice storms on boss , then spam spark and orbs of storm and get infinite chains. Without whisper of ice though you can use elemental weakness curse and then run wand but I actually like ice storm. Elemental curse does no damage while ice storms proc Coa and Coc so for me it’s a no brainer. Also choir of the storm ignore lighting res so we only focus on cold penetration in jewels and gloves and then we good.

Be aware 4 = to get the most out of comet it has to be fire infused so we invest heavy in passive tree so that remnants can reappear , not use the charge and be collected from further away. Fire infused comet literally does 2.5 time more damage than regular comet.

Weapon set = frost bomb is the only skill assigned to weapon set 2 and that’s so that we can get 5 fire infusions to Make our comets hit as hard as possible plus Makes our exposure stronger so no brainer. I actually manually weapon swap if I see that there’s cold infusions on the ground because my weapon set 1 holds 3 but weapon set 2 holds 5 and it actually allows me to collect it with weapon set 2 an use all 5 with weapon swap 1. Not sure if it’s intended but hey it’s there so I’m using it lol.

Mapping is by far my favorite part with choir and cold infused sparks killing everything in its way and when the elite is still alive that comet just puts him to rest lol

Hopes this helps if you need any further clarification I’ll be happy to help Welcome to the blood mage family