i use the combo
C
A
C
B
C
B
C
B
B
B
B
BAC/BCA
A- jedi team
B- palp , sith team,
C- any 5 chars with quite high dps( rey, leia, teebo, ahsoka etc)
for me most of the times it matches out perfectly
B team should be palp lead as he lets everyone heal back by landing debuffs
most of the B team faces rebel squads or jedi squads so easy win
in the 12th node use the B team to destroy any high hp taunt(RG etc) and as much as you can remove protection from everyone.
they mostly wont survive but at least the tank will be dead.
A or C teams come in and destroy them.
if even they cant win then try to kill at least 2 more from the opponents( focus on killing the team healer)
the the leftover 2 can be defeated by the reaming team
have at least one backup character for each team( so have 6 A, B,C team characters so in case one dies along the way you will have a replacement)