Your best comp for general dark side node is a DV lead with DN, Tarkin, EP, and GaT. Boba is also very good here for ability block.
Long-term you want to work on your Imperial Troopers (Veers, Shore, DT, Starck, Snow).
Krennic is also an elite lead here and is a good long-term farm.
I'd suggest reading through this thread as there are a few ideas on teams that work.
https://forums.galaxy-of-heroes.starwars.ea.com/discussion/145986/dark-side-tb-findings-guidance-ab-strafe-impact/p1