Sidious might be good, but Maul and Dooku at the same time? I don't know. Depends on whether or not Maul and Dooku had a cohesive plan beforehand. Examine their fighting styles:
Dooku is rather calm. We don't see him as agile nor as restless or aggressive as Maul. Maul was the Sith ninja from hell, but whether or not that would compliment Dooku's style is based on a plan or even the environment. Given the right circumstances, Dooku and Maul could eventually overcome their master, but it would be one hell of a fight.
I don't think the two could work well together, Dooku would try to find a weakness in Sidious his technique and wait longer before actually trying to kill him. Maul would attack like a crazy rabbit and find his dead before Dooku could really do something, if the two were used to each others fighting style's and trained together then yes they could win. But they didn't. They would get their asses handed back to them in a plastic bag