We're planning a one-shot next week, the last bit of Rise of Tiamat with L17 characters. Our players haven't gotten past L8 in any previous campaign. Are there any guides to High Level Tactics, particularly for full casters?

Party is rogue/fighter, arcane archer, moon druid, paladin who hasn't decided his subclass, and whatever I bring. I'm leaning towards Wizard because Wish.

Spoiler: Possible Spoiler for Rise of Tiamat
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We know that we're going to start off in an enormous cavern, with five red Wizards channeling the summoning and Tiamat starting to break through. Our characters will also know what got us to this point, although none of the players do yet.