[3.3] The BVCopter - cast spells by Weapon swapping

Since the trigger rate of CWDT is rather low compared to the amount of cast speed you could get on a real build, you should either use spells that have a high damage-per-cast ratio or duration spells that don't require you to cast them a lot. From my experience, the latter tend to be significantly more powerful.
You can have multiple spell setups, but often you're better off using a really good skill and building around it.

Main Skills
Duration Spells:
Blade Vortex
Cremation
Vaal Molten Shell (works on this build!)

Damage Efficient Spells:
Volatile Dead
Molten Shell
Dark Pact
Firestorm
Arc
Glacial Cascade

Reserving Mana
This build doesn't use any mana at all, so you can reserve as much as you'd like. A Vitality aura should always be used along with the Watcher's Eye jewel that grants life recovery rate.
If you need more armour, you can use Determination, otherwise the best auras are those that increase the damage of your corresponding skill (Hatred, Wrath, Herald of Ash, ...), followed by Purities to increase your maximum resistances.
Your auras are best used in your weapon swaps, as they will not be turned off when you swap. Make sure to put them in the exact same gem position or it won't work.

Supporing gem setups
You can autocast any spell on this build and should make use of this to empower your main skill.
There's are many setups that are not quite apparent, so I'll list a few here.

What's important to note is that you can't trigger CWDT setups in your weapons because they'll reset everytime you weapon swap. They'll only trigger when something attacks you.
However you can proc Vengeance, which you can then support with other gems.

Examples:
Power Charge on Critical
Culling Strike
Combustion
Blind
Maim (on Vengeance)
Any curse
Summon Skeleton (for Dark Pact)
Unearth (for VD/Cremation)
Hypothermia + Vortex

I highly recommend Righteous Fire because it doesn't only give a huge damage multiplier, it will also increase your life regen and allow you to use Divination Distillate in combination with Mind over Matter.

You can briefly disable it with a dousing flask to proc Soul of Arakaali.



You can also proc it with Blood Rage, which will automatically get removed when you socket it in a weapon with CWDT. However, I think the bonus damage from RF is worth the degen.

You want to use as many spells on level 1 CWDT setups as possible, the more flashy the better.
Fire spells like VD, Cremation or Magma Orb tend to cause the most eye-cancer, so you should prioritize those.

You still want to use efficient gem setups, e.g. making the most out of your sockets by supporting multiple skills at once.
An example 4-link would look like this:
CWDT - GMP - Fireball - Cremation

You should prbably use something like an Abyssus to take more physical damage. This means that you can also use CWDT setups in your weapons.

It's worth noting that spells like Bodyswap and Flame Dash can teleport you all over the place which looks really silly.

Also don't forget to turn all your MTX on so everyone knows that you have a lot of money.

Gear:
•Basically I'm using the usual BV caster gear, plus a total of four Insanity weapon to swap between.
•There's a lot of armour on the items to reach the 13000 threshold.
•Watcher's Eye and an Elder Belt are used for the life recovery rate increase.
•I need a lot of extra dex to cast BV, so I got that on my gear aswell.
•Jewels should have life, damage increases and crit multiplier, but you can also get dex and resists.
•There are many different options for flasks, but this is my favorite setup.

Gems:
•I'm using BV as a main skill because I can reach just about 10 stacks with it, supported with Hypothermia, which is activated by Vortex' chilled ground.
•Maim on Vengeance increases physical damage taken by enemies, so it's worth using.
•RF adds a lot of spell damage and triggers the Arakaali Pantheon by using a dousing flask.
•Raging Spirits enhance by regen by a tiny bit more everytime they die, but they can also cause blind along with the Firestorm. If Firestorm lags too much, Skeletons are a good replacement.
•The Offerings in weapons only proc when I take damage from enemies, they are there to protect me from Detonate Dead effects. They are two different spells, so they don't share a cooldown.

Skill Tree

Just a regular Crit Caster Tree that you can find on many builds, picking up 90% skill duration to help with BV sustain.

Alchemist can be picked up for 3 skill points, it's actually really good with Quicksilver, Ruby and Divination Distiillate flasks.


PoB:
https://pastebin.com/ZAYJEUan