I read the title and thought you needed help putting together a Padme GR squad. Think there's a Padme event subforum up now btw for these kinds of questions.
As for the event you will manage just fine if not easily. If you get Dooku to at least g12 and give him a zeta which you should anyway, together with your Nute, Jango, and Asajj, beating the last phase would be comparable in difficulty to taking your arena squad to Galactic War. Could even leave Grievous on the bench b2 or no, nema problem. CG should have released those Sep reworks a couple of months before Padme instead and tuned the event accordingly I guess.