What is your Galactic War squad?

In my opinion, you need a team, which constantly heals itself in a passive way.

I use Vader (L), Nihilus, Sith Assasin, Palp and Shore Trooper only for the first stage. There I only use basic attacks.

Then I switch to Wedge (L), Biggs, Chirrut, Baze and R2. This team does nodes 2 - 11 pretty easy because of the healing abilities from Wedge and Chirrut. If you don´t have chirrut and baze unlocked, you can use Ackbar and Lando instead of them. Lando will finish the nodes faster and Ackbar cleanses and heals your team.

Make sure, that you have all your cooldowns ready after node 5 and 8, so you can finish the pretty hard nodes 6 and 9 more easy.

After finishing node 11, I switch back to my Zader Lead team and because of having more turn meter and all cooldowns available, this team crushes the last node in 90% of all my GK runs. If anything survives, my rebel team ist able to finish it off.