Need build advice=> Fatal flourish champion galvanic arrow miner

So fatal flourish allows your attacks to repeat, crucible passive allows galvanic arrow to repeat when used with mines. Champion for defences. beyond that i don't know what to build into.
Do I Stack dexterity? Do I use prototype doryani? is more arrows useful so i should look for bow and quiver with more arrows? Or should i use conversion to cold, or even full conversion to chaos with Voltaxic Rift.
What would be some mandatory Keystones?
Any input and ideas would be appreciated.

Saw your post and made a quick PoB with the basic mechanics. I made the Pob with very good items and it still only got about 35M dps. I don't think the mechanics are strong enough to make anything insane because there is no crazy synergy giving it the damage it would need to do well. My version just want to top right and got lightning / trap and mine clusters, otherwise I scaled lots of crit and flat dmg.

https://pobb.in/fiHat04TGu5Q