I meant eup (ethereal upgraded, for those that dunno) viper of course.
The soj rings are good, but kind of a clichè. I like the good rare or crafted rings personally. 10% fcr with some meaty stats.
I mean fcr wise, you get potentially
Griffon 20%
Spirit 25-35%
/ Escutas 40%
Spirit shield 25-35%
Viper 30%
/ Enigma 0% but great frw which can help somewhat
Amulet 10-20%
Rings 10-20% (20% both)
So with this, that's a minimum of 130, and maximum of 200. That's enough to serve most fcr needs...
That leads me to the belt. There is arachnid mesh, for another 20% fcr if you need it. But you know, choosing a good defensive belt is not a bad option... the string of ears is a very good defensive option. You can choose any defensive belt. Like thundergod's vigor if venturing into strong lightning monster areas...
But as to the point of hardcore, no matter how expensive gear you buy, if you play recklessly, you will die sooner or later anyway. So there is a point of caution always. But this kind of gear will make you quite strong. You cannot simply tank everything as a sorc anyway. But the lightning will deal sick damage and break through most things.
The merc... well, infinity is an obvious choice, personally i don't like it so much. The aura takes 0.5 seconds to take effect, after a teleport, that's very annoying. Sometimes more too. The merc has to be in the area of monstes to make it work. Self-wielding, i've tried that as a nova+lightning sorc, it works very well. You cannot get 200% fcr though, but you are going lightning, so only for the teleport, not absolutely necessary.
Actually, reaper is a good choice, slow enemies down a bit, and deal with lightning immunes, AND provide protection from ambushes. Still, there is also insight+prayer, gives insane regen, never have to worry about mana running out. That can be a frustration point. Doing pots all the time is amateurish.
There are many choices to consider. It all depends on your style........