Plutarch's plan for the rebellion before the third QQ twist

In the books it's not Plutarch's idea to reap the tributes among the remaining victors, but Snow's. Before that twist, Plutarch assumed Katniss was going to be a mentor (I haven't read the books yet but this much I know). How do you think he'd “use” her to fuel the rebellion in this scenario? Was he planning to sabotage the 75th games in the same way he actually did anyway (but not to rescue Katniss, of course)? Or would he wait until after the games to somehow contact Katniss and bring her in on the plan? Or, again, in his original plan the rebels would have raided the Capitol without Katniss' physical presence? If that's not mentioned in the books, feel free to share your theory, I'd love to hear it!