there has to be more... i hate waiting for the respawns!

This is a long boring quest that is extremely eaasy to solo. You are better to kill as many as you can, and move onto another quest and come back and kill some more. The respawn rate for these guys seems like it takes forever, so worl it ion with other quest.

If you have an hour to kill, then hang out and wait.

kinda easy if are in group with at least one

Okay, finished this at level 14 using the VW not the imp, should work lower as none of the spells I used were upgraded at 14.

First, if you have any cash handy, get a wand. By picking up skinning and selling what I skinned on earlier quests, I had enough money to grab a greater magic wand, but a lower one will do. You just want something you can use without interruption when you get hit.

Second, don't pull. As doorslam mentioned, although there's no "immune" message, torment doesn't do a thing. Also, your pet doesn't hit very hard - even one DOT before he's gotten in a little damage can end up building up way more aggro than he can manage to take off, and harvest watchers rip through cloth wearers fast.

Start at one end of the field and keep an eye on the wandering pattern. When an HW is at a point where facing him won't draw the aggro of those around him, send in the VW. Let him get in two, maybe three successful hits. It doesn't take many, and at that point you can safely use curse of agony. After that, just wait another couple seconds for the VW and the DOT to take about 1/6th of life off the HW. At this point, forget the other DOTs - as I said, they're too prone to draw aggro and take long enough to kill that your health suffers for it. Instead, throw off two shadow bolts in a row. That'll definitely draw aggro, but at that point you'll have taken him down to where a couple shots with the wand will finish him off, even once he does start hitting you.

Doing it this way, and logging on early in the morning to avoid competition and messy respawns, I killed constantly and went from 2 killed to 20 in about 20 minutes.

Also, on a side note, I spotted a level 14 warlock using an imp just after I did the quest turn-in, so I stopped to compare - one fight took nearly all his health and the kill was slower.