Level 72 - In GW I run Lumi (L), QGJ, Aayla, Sun Fac, and Royal Guard all the way through. Sometimes I sub in Ackbar if I need a clense. (I finish GW 9/10 times)
Running Lumi (L) is good for the battle of attrition. Everyone gains health every turn they take.
Having a good tank will go a long way too.
A triple heal would probably let you through most of GW. Maybe try Lumi (L), Boba, Lando, Ackbar, and either JC or Barris.
Also you can always retreat and restart a global war match if you have some bad luck. You can try a different combination.