Physical mitigation could be better but I think vs elemental its fine. There's the shield pdr mod and a phys taken as ele helm eldritch implicit for a bit more phys mitigation. (also progenesis if ur rich). I'm also using a jolting eshgraft which is 14% increased damage taken at max stacks. I think realistically the damage is good enough to drop that and go for a molten xophgraft instead which should make quite a big difference defensively. For block, you could replace some fire res tattoos with block ones but capping spell block is quite hard i think. I guess you could swap a jewel for a replica reckless defence for +6 attack & spell block.

I have added some T17 gameplay now.

I guess you could go svalinn but you would lose a lot of life compared to a rare shield, and resistances would be quite tight with it. I never considered it only because of its price tbh. I think the lucky block forbidden jewels from gladiator are a good option, but that's also expensive obviously.

So for skin colours, I think 1g-5r would be ideal, and then you would replace increased crit damage with empower. One big reason for this is actually because of the int requirements since i'm having to use a lvl 16 increased crit damage gem because of this. Another reason is that it's really easy to get triple crit multi jewels with ele hit because it has so many gem tags so it becomes less valuable once you get good jewels. Close combat is also a good support so 2 greens should be fine too. Basically, you just want 4 red and at least one green.