My v/t tanked at least 15-20 fireballs from the former #1 fireball sorc. She's got about 15k dmg and is an ES WHORE. VanGosroth has about 3,600 hp when in resist mode though. More then what most necros have. If your skilled enough, noko + spurs + max res SHOULD be enough. If not pop on them dwarfs! Add some sorb and you'll be fine.

If even then you cant win its for one of two reasons. 1) She's a tele whore, 2) You need practice.

Oh, and i know someones going to say "Well VanGosroth is a V/t and were talking about a PNB necro". I don't use tele on him and my charge does 1/4th the dmg a single bone spear does. It balances out.