Splitting Steel Champ Upgrade Choices

So thank you to those who recommended going with Splitting Steel, going really well.

My question is, beyond swapping my 2nd ring out, gaining a level to utilise a "That Which Was Taken" jewel (chance to gain power charge + crit chance with max charges, got a spare point in large cluster to move), to then change my charms around for some impales ones... Would that be as far as it would be worth it to min-max?

I've only got around 30 divs leftover, so the choice is to save for the upgrades if worth it, or save all upcoming divs for a new PF FR build.

It seems if I go the Forbidden Flame/Flesh, better Watcher's Eye or even the Progenesis route, the pricing (I think 80 div +) doesn't give as much of a worthy impact?

https://pobb.in/TaEKdjV0Q6op

Usually just copy build guides, with a slight change here and there, not used to setting this up, which is also why I can't really see if when I put Progenesis etc into my build, it makes much of a difference.

My goal, which I feel is nearly there, was an all rounder character, hitting some juiced maps, and for my first time ever having got 4 Voidstones. I just don't want to waste the divs if there's going to be no extreme extra tankiness, or damage to those juiced rares.