It was a few years ago, my roster is mostly at relics right now, but IIRC my Padme team was probably G12, at most G13 (i.e, R0). But I think I used Padme, GK, Ahsoka, Shaak-Ti and C3P0. Try to put Confusion on the MagmaDroids, then focus down on B2 so he doesn't keep dispelling your buffs. After that, whittle down B1. Then, go for Magmas to get DDK shields down, preferably when you have enough Courage from Padme on you. Once you're down to just Grievous, try to have ProtUp on you so Grievous can't crit you. Good news, even though he's tagged as a boss, is you can still stun him. Best case scenario, you have max stacks of Translate on Padme, so every time you use his basic Padme's stun ability has its cooldown lowered. I think up until then, the most you have to worry about is DDKs constantly assisting against you.