why not use the vipermagie with 32 res instead of stealth ? It would give you some decent res and a + skill ?

Asking because I am facing the same issue with my trap assassin and that's what I was thinking about doing. What do you think ?

That's actually a pretty solid idea. Didn't think about that actually. I wouldn't solve my res still as my lowest would be 59 Lightning, and want to cap Fire, Cold and Lightning to Hell.
But if it works for you I would totally go with Vipermagi for the ekstra +1 Skills. Could I cap my res with it I would anyday use it over Smoke. Thanks for the suggestion.