Do you have Mas Amedda? Ideally you'd use him to get the best out of Thrawn's Commander Effects - you can use board-wide swap, rather than just swapping two pieces from within 6 of Thrawn.
The core pieces of:
50 Darth Vader, Unleashed
33 Emperor Palpatine on Throne
32 Thrawn (Mitth'raw'nuruodo)
31 Arica
Are pretty good - from there, I'd just use Mas Amedda, plus some filler pieces like Rodian Brutes (for swapping), an R7 or Lobot (for override), and Ugnaught Demolitionists (for Satchel Charge).
Weeks, who finished first after Swiss at GenCon last year, posted this squad a while back - it uses all four of the main pieces in your squad:
http://www.bloomilk.com/Squad/91452/choke