Single target fight - Zeal + BoJ
3+ target fight - TFoJ + DH
As for leggos, sim it. 2p T19 and 4p T20 is our best set so you'd use Ring/Belt, but only if the T19 pieces are high enough to be competitive with ToS gear (basically Mythic or HC TF ilevels).
Personally I find myself hardly using Zeal in my rotation, if I'm lucky with BoW procs so you definitely don't want TFoJ with 4P as you'd probably waste HP.