I actually haven't done challenge of elders until yesterday. Figured to go in solo see how it is. First two are pretty easy, but yeah like you said the cabal one is a pain. Luckily though once you manage to take the flayers out it's smooth sailing after that. Swords seem to be really good for that. Takes too long to shoot them when they bobbin around. I was running sunsinger to have that extra safety blanket, but then I realized in order to get the weapon I need to make the 30000 points in one game -_- so I'm going to run stormcaller this time and see if I can get 30000. If not I'll probably just try and find a group. You should probably use bladedancer. Too hard to get super kills with nightstalker