Yeah, I just saw that in the other thread 
I didn’t make one at the time because I assumed it wouldn’t be great. (Bear in mind that I wrote this guide during the playtest, so it’s likely not as good as I had hoped it could be)
As far as what I have tried and seen, the stormfang set allows you to stack onslaught with winds of Asterkarn, andn spend them on devastation. That’s probably one of your best choices for that Here’s a quick doodle of what I mean: Evoker, Level 100 (GD 1.3.1.0) - Grim Dawn Build Calculator
Also, like I mentionned, this guide is probably outdated already, but you can find a lot of good info on onslaught here: [1.3.0.8-1.3.1.1] Fangs of Asterkarn: In-Depth Mechanics & Testing