I had no problem with Voss quests using carnage tree.
I think your problem is not your gear, but your companion. Quinn is not a good option with carnage, as it’s all about burst, u need a companion that can help you burst. I used Jaessa all the way from 30~ to 50 and soloed all the class content. Remember to keep your companion gear up to date .
With Jaessa or Vette, pop ur defensive cds, saber ward, cloak of pain and Call On The Force if u think u’ll need it (remember it refreshes your saber ward), charge one of them and dps the crap out of it.. you should kill it before being 50/60% health. Then use force camuflage to lose agro and start dpsing immediately so u can take agro before it kills your companion. I think that should do it, as it worked for me in difficult fights.