any good sorcerer guides out there?

[the Langolier]

Here you will see Dr. Disaster's TeleFlash Guide, a very efficient tactic on Nightmare/Hell and Hell/Hell.

I would say effective rather than effecient. Let's say you come across two balrogs. 40+40 mana to stone, 15 to teleport, 18x2 to flash. That comes to 131 mana for two enemies (150 if you need a third flash). That is pretty expensive for only two enemies.

I prefer to postition myself behind all the balrogs and cast chain lightning once or twice to take the whole crowd down a bit. I then alternate between flash and chain lightning as the enemies move close. The best spot to do this is is in a northwest corner. This postition will focus the CL much more effectively, and will prevent enemies from entering the tiles where flash does minimal damage. Use CL to hit everything until an enemy goes to move next to you. At that point, hotkey to flash and cast it double. You will be invulnerable to their melee attack as your spell finishes the balrog off.