So I play DH near exclusively, but had accumulated over that course several Firebird pieces, including an INT furnace.
Spent a couple hours and got the remaining pieces from Kadala. Rerolled some DEX/Fire gears, ran a few T6 rifts to get the feel for how it all works, and then jumped right into greater rifts. Cleared all the way to 39 with just one failure, not too shabby in just a night eh. Tbh, a large part of it comes down to Firebird playing very much like M6. Faster damage ramp up, but lower damage ceiling. Otherwise, many of the cheese tactics in the M6 playbook apply to Firebird.