Self-Chill builds (Hydrosphere)

https://pobb.in/OYm3R8A60Ejm Only a proof-of concept as I had a previously leveled witch.

I haven't played a self-chill build before so I did some reading of possible builds. I know that people usually do it with Lightning/molten strike for attacks or spark for spells. I have another combo I want to try this with: Hydrosphere Vortex. The idea is to use vortex on m1 which should clear trash but also inflict a freeze/brittle on Hydro. Hydro has a bunch of extra levels + crit so should be good enough for map bosses/guardians.

The method for Self-chill is Winterweave, Call of the Void + FR. I have seen a bunch of people straight up main skilling FR to achieve 100% chill uptime. I have also experimented with a aisling 4sec cd trigger. Without other investment, seemed like I got 1.5s of 30% chill every 4 seconds. I currently have allocated Breath of Rime and Lethe Shade which gives me 100% uptime given I have enough mana. The latter, as you can see in pob, takes far too many points to reach. I suppose the solution to this would be to swap to a Lethe Shade Skin of the Lords, but there aren't any on trade with my colors.

Am I missing anything else in terms of self-chill duration? I haven't seen much other CotV + FR set ups.

I would prefer to fit in Righteous Fire to help clear trash and the more spell dmg. I managed to reach 90/90/90 with Melding of the Flesh and I would really prefer to keep this, as it's one of the only defense layers I have.

On Ailments and max resist I am currently using Leadership's Price to for the +3 max fire res and ailments. I am not sure if I like this or not, or if it really makes any difference in dps but: Vortex with this setup applies Brittle AND Sap to hydrosphere which converts 50%/50% cold lightning. The main benefit of this is that I don't need to hit 100% crit chance to apply freeze on hydrosphere. I think the only damage I lose by applying sap is via Hatred's cold damage bonus? Perhaps some brittle effect? It's not something I can calculate and compare easily, as I don't know what changes I would need to achieve 100% freeze chance. It's kind of a hard drop as it also allows me to drop Prismatic Skin wheel for 4 passive points.

On Mana management it is currently... alright. I have enough reservation efficiency for normal handcasting my main spells. But recovery is not enough to 100% reliably trigger wand spells which drops the chill sometimes =( My idea for a solution involves dropping a second curse for lifetap on wand so it reliably triggers FR+MS. I really don't like self-casting two curses so I will probably change ascendency too. The other solutions I can think of is to drop my lvl 1 precision for lvl 1 clarity + watchers eye or spend another 3-4 passives for another mana mastery.

It's a weird passive tree... I path between maurader/duelist originally because of Prismatic Skin+Soul of Steel for max res. But with Leadership's Price, I dropped Prismatic Skin. I'm also getting pretty needed resist from Green Dream + Sentinel socket in the middle, but I have thought about maybe grabbing the res from the shield nodes in templar area instead. I would be losing two jewel sockets as well, so I would think the saved points need to go to a cluster jewel.

Ascendency is flexible as well. I see that people play hydrosphere on Inquisitor for the crit pen. and the conc. ground means I can probably drop vitality. Heirophant looks really interesting with arcane surge ailment scaling and maybe I could fit in another aura with Sanctuary of Thought?

It really feels like I have all the right ingredients. I have pretty good gear and things seem to work but not perfectly. Could you all suggest optimizations? or should some of the core elements I mentioned be changed? I think next league I will probably do another 100% uptime self-chill build, but just simply with spark or something