Was always one of the toughest fights in the game. But if I remember right, only two of them hit particularly hard - the other two just fanny about teleporting and trying to put people to sleep. So I've always kept most of the party separated, on the bridge (for pushing antics), sent my tankiest tank down with ideally 19-20AC, summoned an imp or spider or whatever other decent familiar is available, swallowed a bunch of potions of speed and hill giant strength, and concentrated on the two big hitters. Usually had one team member downed but rarely worse.
However. I am about to take them on for the first time since the patch. So, WML
The +1 weapons make a huge difference. Less likely to miss and hit harder...
