I'm currently working on building a heroic Rancor team so that I can actually get somewhat decent raid rewards. Here's what I'm thinking, based on what I have to work with. https://swgoh.gg/p/74867792...
Another tip, don't culling blade with Vader unless the door is down. That will remove Tenacity Down and Slow. But if the door is down, you can Culling Blade first then use Tie Fighter Pilot to inflict Tenacity Down again.