You do need the FCR because it allows you to change your setup. You should want to use both SOJS because you're ES and that's what ES sorcs do. I'd actually switch to vipermagi. This keeps some resist, and gives you an additional 30 fcr. Now you can replace the fcr ring with a soj. Your next move isn't conventional, but it's the best idea by far. Switch arach with a 24/30/60 (fhr/str/life) belt [or the best you can get]. This will help more than a single fcr ring with the str req for spirit, give a huge life mod, and give fhr. You don't lose a skill cause you switch FCR ring for SOJ, so the skill from arach is negligible. You lose 1 skill from Vmagi, but it's worth it for the extra mana, str, fhr, and life.