Arena PVP Best Compisition

Hey all I am 59 using the following for PVP:
Sidious (Leader) / IG-86 / Daka / HK-47 / Vader
Vader and Daka are my two 4 Stars. Sid/IG/HK are 7 Stars.

My question:
Since Vader will not scale well, I was wonder if it would be worth replacing him, and putting my 4 Star Phasma as team Lead?

I also have the following 4 Stars and am looking for thoughts on the best team Comp:
F.O. Tie Pilot / Barris Offee / Luminara Unduli / Chewbacca / Counsular / Obi-Wan /

Thanks,
B