You mind going into more detail about how you farmed 15 sunders?
Also was your zerk barb doing p1 or p8 and how did you deal with thorns aura?
1) play a lot, play efficiently
2) kill heralds on p8/2+, I used a 2nd account on nova to try to hork extra sunders but all of them came from the initial drop. However, among all the sunders I've seen drop including the ones I didn't loot myself I'd say 90% had 2p or more in kill area. I know p8/2 supposedly adds only 5% or whatever no drop but it feels like it matters a lot. Anecdotal i know
3) zerk generated half the sunders much faster - if you are tired of killing solo you can just switch to horking heralds. In eu pubs almost everyone is chill about it. Or do both
The whole point of playing zerk was to dodge thorns, but I was still taking some damage from it, not sure why? Just used rejuvs to outheal it