[Pre 3.22] Scion Cold Dot questions

Hello, I am planning to league start 3.22 with Scion (Occu/Raider) Cold Dot (Vortex/Creeping Frost/Cold Snap)
Something like Jungroan's Scion Cold Dot build (https://pobb.in/JXCnitjm) but I have never played scion builds so zero experience in leveling scion

Could someone please guide me:
- leveling scion into Cold Dot
- item priority & gear progression if it's possible

I am planning to level using gems like this:
- Act 1:
-- Stormblast mines - Swift Assembly - Added Lightning Damage
-- Frostbomb
-- frost blink -> Flame dash

- Act 2:
-- Cold Snap - Bonechill - Efficacy - Controlled Destruction
-- Aura: Herald of Lightning & Herald of Ice

- Act 3:
-- Level 28: Vortex + Creeping Frost
--- Vortex - Controlled Destruction - Swift Affliction - Elemental Focus
--- Creeping Frost - Controlled Destruction - Swift Affliction - Elemental Focus
-- Aura: Malevolence
-- Curse: Frostbite

- Act 4-10:
-- Allocate: Whispers of Doom -> Add Elemental weakness
-- Faster Attacks - Shield Charge
-- Molten Shell - CWDT / Determination Aura

Could someone help suggest a leveling passive tree please?

I am planning to go cold dot as well
I will cook something on Friday before league start

Probably use main skill plus a totem for damage
Or I will copy one of the Elementalist guides

The start will be rough, we need to path toward damage nodes
Also the ascendancy does no good till we get at least 3 labs.

Oh btw use creeping frost as soon as you get it, creeping forst with volley support. because hit damage is big early in the acts.