Been hunting here recently with my SB. Got the belt on about the 12th kill but that is the only piece so far.
They are places in 3 small groups of 3. You can easily solo here just make sure you are not in assist range of the other two. They cast when pulled but I have only been nuked once (64 dmg) and that was when I got an add.
Con Yellow at level 16 and Yellow/OJ at 15 so the level guide is correct.
Fairly easy to solo with my 2HD axe. I open with Backstab II/Follow-up, Lethal Poison and Hamstring when able. I end with 50% - 80% HP each time easily. Not great xp by any means but the loot is well worth it and they are nice easy pulls.
If initial poison is resisted it is harder but I always keep an extra weapon or two poisoned for emergencies.