I did it on my stam sorc, finally. If anyone wants to know I was simply running hundings, spriggans with blue jewelry, velidreth with one off trait in 5 medium and 2 heavy, nothing special and a ways from bis. Though I am at CP cap. Last round took me about two hours to beat as I'd gone up until that point and left the quest sitting for a month or so. When I finally beat him it went very quickly. Dropped down from the top, defense sigil, power sigil, gold ghost stun, bursted him down in no time. All in all only went through about 20 tri pots on that last round. Will I ever get flawless? I doubt it. Will I go farm it again? Probably. Thanks to various content creators and streamers who have helped me with guides and builds, especially
@Lukums1 for the guides he has put up and of course
@Alcast for getting me started in the game and always being a good point of reference for pve builds.
Tips for those yet to complete the last round:
1. For the love of the gods interrupt the archers about to focus aim you
2. Get your rhythm for destroying crystals, even when you can't outright burn one. When you're following the stone shield leave dots on the ones you pass and for stam users drop a rearming trap on those crystals. It helps burst them down a lot faster.
3. Also for stam users, on your first clear you might benefit from using the interrupt morph of poison arrow. It made interupting Voriak a lot easier and you often get random interrupts on adds which I felt was useful.
4. Above all DO NOT let Voriak get a gold ghost.
What did I get? Good ol' one hand and shield.
Good luck to those still fighting it out.