Grievous lead with Wat, Spy, Sun Fac, Brood Alpha. Put weapon tech on Grievous so when he kills someone they can't be revived. As soon as Brute dies get the B2 Droid out there and put the tank tech on it. Wat needs as much health as you can get so he survives and can revive everyone.
It wasn't super easy, but I also did it with Spy and Sun Fac at g12, Brood Alpha was r3 and Grievous/Wat were r7, so more relic levels would make it easier.
This frees up the Droids to use in the Dooku mission which was pretty easy
