Trying to make a spark charge build

Picked up Fragment of the Enigma - Unique Rune Stone - Off-Hand Catalyst - Last Epoch Item Database
Noticed it gives a lot of damage if I stack intelligence and trigger lots of spark charges.

The question is what would be the best way to go about this build, I know lightning blast, elemental nova and teleport are the main skills, as all three help with applying charges.

But what would be the setup for their trees? And what would be the gear affixes to look for(I do not know much about mage affixes)? Also would there be any uniques to look out for besides the build enabling item and the heart of Uhkeiros?

You can either go lightning blast caster mage like you are thinking.
Or go spellblade and use surge etc.

spellblade does complicate things a little, but you are probably right. concidering that the unique gives a more mult to melee dealt spark charges AND surge has a more mult to its own spark charge, it probably will hit like a truck.

Should also have a clear option: mana strike specced into the mana storm setup with lightning charges added. Though the exact nodes I pick I am unsure of. Or maybe just lightning blast, because it hits the entire screen.

regardless of which one, the weapon is going to be a sword, because it has to be for the surge spark charge nodes, this results in a really small amount of flat spell damage from weapon(thus why int becomes very important for every other slot). I am unsure of any other uniques that would be super useful, Vilatras storm crown is penetration and some shock chance that scales with int(shame I cannot get the set here), invokers rings have added flat lightning spell damage(but no int) Oceareon makes shock stacks do lots of damage.

I cannot think of much more options for gear, and I am probably missing some crazy defensive gear in the build.

So now that that is out of the way, the question is what idols/passives should be taken, I think attack speed + spell lightning + spell crit +int is priority. Also generating ward on hit. I am unsure of the exact passive setup though.

And I am COMPLETELY lost when it comes to optimal idol setup.