When you use the Furnace, you skew the balance away from fire damage toward elite damage. I have ~35% fire dmg (SoJ, Strongarm), 85% elite dmg. This may seem like a trade off that's not worth it, but don't forget you're adding the much, much higher 2hr base dmg for the firebird dot. I could get more fire damage if I had a perfectly rolled amulet where I could roll off the int for 20% fire, but meh.
CDR isn't necessary, nor Evocation (Illusionist, Unstable Anomaly, Blur, Glass Cannon). You want armor or all resistance rather than CDR. Illusionist means that in high GR, every time you get touched your Teleport is up. It would be nice to cast faster black holes, but it's not worth the trade off. Glass Cannon is necessary as you need to do as much damage as possible. With Blur, String of Ears, and 500k+ hp, you can survive at least 2-3 hits.
I can do 39 quite easily now. While I could do 39 with my SunKeeper + Firebird's Eye, that was a one time thing and I had only 30 seconds to spare. I couldn't repeat that performance with SunKeeper. With a perfect rift, I could probably do 40/41, but I don't think it's worth the effort.
T6 is a joke no matter what you use. As fast as you can cast blizzard + black hole things will die. You honestly don't even really need conduit. When you do T6, you don't need Blur or Unstable Anomaly, so you can throw in Evocation and Astral Presence (for continuous Blizzard usage). Doing grouped t6 is definitely slower than solo, but I suppose the magic find makes up for it.
