just lost a 5 v 1 to a dooku under DN lead - lol

I'm similar to you OP. My second account I also used droids in arena and am at lvl70. At this lvl I find DN lead sith teams are very easy...unless they have Dooku, that dude and his multi counter + steal heal can mow down the team in a flash. Try to minimize your droids attacking him and just put JE's detonators on him (no counterattack)...by the time he is the last target hopefully the detonators have done their job softening him up.