I always find myself starved for force on Vader.
Often the first engagement I burn 2 before even shooting (SR + Focus)
I also often find it hard to stick on one target with him because I believe stress is the enemy (still adapting from 1.0 Vader) so every other turn I'll burn a force for an action.
The real question for me with Vader is if I have 1 eye result and another shot incoming, do I spend the force or the focus?